Index: Ringtoets/DuneErosion/src/Ringtoets.DuneErosion.Data/DuneErosionFailureMechanismAssemblyFactory.cs
===================================================================
diff -u -r8554c8723c3d665efd0a9d5e0ea48e7494ee680d -r63e0ee80a5f8d6352ff172c693df3dc749b2828d
--- Ringtoets/DuneErosion/src/Ringtoets.DuneErosion.Data/DuneErosionFailureMechanismAssemblyFactory.cs	(.../DuneErosionFailureMechanismAssemblyFactory.cs)	(revision 8554c8723c3d665efd0a9d5e0ea48e7494ee680d)
+++ Ringtoets/DuneErosion/src/Ringtoets.DuneErosion.Data/DuneErosionFailureMechanismAssemblyFactory.cs	(.../DuneErosionFailureMechanismAssemblyFactory.cs)	(revision 63e0ee80a5f8d6352ff172c693df3dc749b2828d)
@@ -183,19 +183,21 @@
         /// Gets the assembly category group of the given <paramref name="failureMechanismSectionResult"/>.
         /// </summary>
         /// <param name="failureMechanismSectionResult">The failure mechanism section result to get the assembly category group for.</param>
+        /// <param name="useManual">Indicator that determines whether the manual assembly should be considered when assembling the result.</param>
         /// <returns>A <see cref="FailureMechanismSectionAssemblyCategoryGroup"/>.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="failureMechanismSectionResult"/> is <c>null</c>.</exception>
         /// <exception cref="AssemblyException">Thrown when the <see cref="FailureMechanismSectionAssemblyCategoryGroup"/>
         /// could not be created.</exception>
         public static FailureMechanismSectionAssemblyCategoryGroup GetSectionAssemblyCategoryGroup(
-            DuneErosionFailureMechanismSectionResult failureMechanismSectionResult)
+            DuneErosionFailureMechanismSectionResult failureMechanismSectionResult,
+            bool useManual)
         {
             if (failureMechanismSectionResult == null)
             {
                 throw new ArgumentNullException(nameof(failureMechanismSectionResult));
             }
 
-            return failureMechanismSectionResult.UseManualAssemblyCategoryGroup
+            return failureMechanismSectionResult.UseManualAssemblyCategoryGroup && useManual
                        ? failureMechanismSectionResult.ManualAssemblyCategoryGroup
                        : AssembleCombinedAssessment(failureMechanismSectionResult);
         }
@@ -204,12 +206,14 @@
         /// Assembles the failure mechanism assembly.
         /// </summary>
         /// <param name="failureMechanism">The failure mechanism to assemble for.</param>
+        /// <param name="useManual">Indicator that determines whether the manual assembly should be considered when assembling the result.</param>
         /// <returns>A <see cref="FailureMechanismAssemblyCategoryGroup"/>.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="failureMechanism"/>
         /// is <c>null</c>.</exception>
         /// <exception cref="AssemblyException">Thrown when the <see cref="FailureMechanismAssemblyCategoryGroup"/>
         /// could not be created.</exception>
-        public static FailureMechanismAssemblyCategoryGroup AssembleFailureMechanism(DuneErosionFailureMechanism failureMechanism)
+        public static FailureMechanismAssemblyCategoryGroup AssembleFailureMechanism(DuneErosionFailureMechanism failureMechanism,
+                                                                                     bool useManual)
         {
             if (failureMechanism == null)
             {
@@ -224,7 +228,7 @@
             try
             {
                 IEnumerable<FailureMechanismSectionAssemblyCategoryGroup> sectionAssemblies =
-                    failureMechanism.SectionResults.Select(GetSectionAssemblyCategoryGroup).ToArray();
+                    failureMechanism.SectionResults.Select(result => GetSectionAssemblyCategoryGroup(result, useManual)).ToArray();
 
                 IAssemblyToolCalculatorFactory calculatorFactory = AssemblyToolCalculatorFactory.Instance;
                 IFailureMechanismAssemblyCalculator calculator =
Index: Ringtoets/DuneErosion/src/Ringtoets.DuneErosion.Forms/Views/DuneErosionFailureMechanismResultView.cs
===================================================================
diff -u -r7adc47fc72205078d054034bb9d1028c32434e28 -r63e0ee80a5f8d6352ff172c693df3dc749b2828d
--- Ringtoets/DuneErosion/src/Ringtoets.DuneErosion.Forms/Views/DuneErosionFailureMechanismResultView.cs	(.../DuneErosionFailureMechanismResultView.cs)	(revision 7adc47fc72205078d054034bb9d1028c32434e28)
+++ Ringtoets/DuneErosion/src/Ringtoets.DuneErosion.Forms/Views/DuneErosionFailureMechanismResultView.cs	(.../DuneErosionFailureMechanismResultView.cs)	(revision 63e0ee80a5f8d6352ff172c693df3dc749b2828d)
@@ -140,7 +140,7 @@
 
         protected override void UpdateAssemblyResultControl()
         {
-            FailureMechanismAssemblyResultControl.SetAssemblyResult(DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(FailureMechanism));
+            FailureMechanismAssemblyResultControl.SetAssemblyResult(DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(FailureMechanism, true));
         }
 
         protected override bool HasManualAssemblyResults()
Index: Ringtoets/DuneErosion/test/Ringtoets.DuneErosion.Data.Test/DuneErosionFailureMechanismAssemblyFactoryTest.cs
===================================================================
diff -u -rc1ad8e8431d65da2f22adeb93f9deddd9fae77e3 -r63e0ee80a5f8d6352ff172c693df3dc749b2828d
--- Ringtoets/DuneErosion/test/Ringtoets.DuneErosion.Data.Test/DuneErosionFailureMechanismAssemblyFactoryTest.cs	(.../DuneErosionFailureMechanismAssemblyFactoryTest.cs)	(revision c1ad8e8431d65da2f22adeb93f9deddd9fae77e3)
+++ Ringtoets/DuneErosion/test/Ringtoets.DuneErosion.Data.Test/DuneErosionFailureMechanismAssemblyFactoryTest.cs	(.../DuneErosionFailureMechanismAssemblyFactoryTest.cs)	(revision 63e0ee80a5f8d6352ff172c693df3dc749b2828d)
@@ -65,8 +65,8 @@
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
 
                 // Call
                 DuneErosionFailureMechanismAssemblyFactory.AssembleSimpleAssessment(sectionResult);
@@ -85,8 +85,8 @@
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
 
                 // Call
                 FailureMechanismSectionAssemblyCategoryGroup actualOutput =
@@ -106,8 +106,8 @@
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
                 calculator.ThrowExceptionOnCalculate = true;
 
                 // Call
@@ -153,8 +153,8 @@
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
 
                 // Call
                 DuneErosionFailureMechanismAssemblyFactory.AssembleDetailedAssessment(sectionResult);
@@ -177,8 +177,8 @@
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
 
                 // Call
                 FailureMechanismSectionAssemblyCategoryGroup actualOutput =
@@ -198,8 +198,8 @@
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
                 calculator.ThrowExceptionOnCalculate = true;
 
                 // Call
@@ -241,8 +241,8 @@
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
 
                 // Call
                 DuneErosionFailureMechanismAssemblyFactory.AssembleTailorMadeAssessment(sectionResult);
@@ -261,8 +261,8 @@
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
 
                 // Call
                 FailureMechanismSectionAssemblyCategoryGroup actualOutput =
@@ -282,8 +282,8 @@
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
                 calculator.ThrowExceptionOnCalculate = true;
 
                 // Call
@@ -404,8 +404,8 @@
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
                 calculator.ThrowExceptionOnCalculateCombinedAssembly = true;
 
                 // Call
@@ -429,7 +429,8 @@
         {
             // Call
             TestDelegate call = () => DuneErosionFailureMechanismAssemblyFactory.GetSectionAssemblyCategoryGroup(
-                null);
+                null,
+                new Random(39).NextBoolean());
 
             // Assert
             var exception = Assert.Throws<ArgumentNullException>(call);
@@ -449,7 +450,8 @@
 
                 // Call
                 DuneErosionFailureMechanismAssemblyFactory.GetSectionAssemblyCategoryGroup(
-                    sectionResult);
+                    sectionResult,
+                    new Random(39).NextBoolean());
 
                 // Assert
                 FailureMechanismSectionAssemblyCategoryGroup expectedSimpleAssembly = DuneErosionFailureMechanismAssemblyFactory.AssembleSimpleAssessment(
@@ -475,7 +477,8 @@
             {
                 // Call
                 FailureMechanismSectionAssemblyCategoryGroup categoryGroup = DuneErosionFailureMechanismAssemblyFactory.GetSectionAssemblyCategoryGroup(
-                    sectionResult);
+                    sectionResult,
+                    new Random(39).NextBoolean());
 
                 // Assert
                 FailureMechanismSectionAssemblyCategoryGroup expectedAssembly = DuneErosionFailureMechanismAssemblyFactory.AssembleCombinedAssessment(
@@ -485,7 +488,7 @@
         }
 
         [Test]
-        public void GetSectionAssemblyCategoryGroup_WithManualInput_ReturnsOutput()
+        public void GetSectionAssemblyCategoryGroup_WithManualInputAndUseManualTrue_ReturnsOutput()
         {
             // Setup
             var sectionResult = new DuneErosionFailureMechanismSectionResult(FailureMechanismSectionTestFactory.CreateFailureMechanismSection())
@@ -496,27 +499,52 @@
 
             // Call
             FailureMechanismSectionAssemblyCategoryGroup categoryGroup = DuneErosionFailureMechanismAssemblyFactory.GetSectionAssemblyCategoryGroup(
-                sectionResult);
+                sectionResult,
+                true);
 
             // Assert
             Assert.AreEqual(sectionResult.ManualAssemblyCategoryGroup, categoryGroup);
         }
 
         [Test]
+        public void GetSectionAssemblyCategoryGroup_WithManualInputAndUseManualFalse_ReturnsOutput()
+        {
+            // Setup
+            var random = new Random(39);
+            var sectionResult = new DuneErosionFailureMechanismSectionResult(FailureMechanismSectionTestFactory.CreateFailureMechanismSection())
+            {
+                UseManualAssemblyCategoryGroup = true,
+                ManualAssemblyCategoryGroup = random.NextEnumValue<FailureMechanismSectionAssemblyCategoryGroup>(),
+                TailorMadeAssessmentResult = random.NextEnumValue<TailorMadeAssessmentCategoryGroupResultType>()
+            };
+
+            // Call
+            FailureMechanismSectionAssemblyCategoryGroup categoryGroup = DuneErosionFailureMechanismAssemblyFactory.GetSectionAssemblyCategoryGroup(
+                sectionResult,
+                false);
+
+            // Assert
+            FailureMechanismSectionAssemblyCategoryGroup expectedAssembly = DuneErosionFailureMechanismAssemblyFactory.AssembleCombinedAssessment(
+                sectionResult);
+            Assert.AreEqual(expectedAssembly, categoryGroup);
+        }
+
+        [Test]
         public void GetSectionAssemblyCategoryGroup_WithoutManualInputAndCalculatorThrowsException_ThrowsAssemblyException()
         {
             // Setup
             var sectionResult = new DuneErosionFailureMechanismSectionResult(FailureMechanismSectionTestFactory.CreateFailureMechanismSection());
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
                 calculator.ThrowExceptionOnCalculateCombinedAssembly = true;
 
                 // Call
                 TestDelegate call = () => DuneErosionFailureMechanismAssemblyFactory.GetSectionAssemblyCategoryGroup(
-                    sectionResult);
+                    sectionResult,
+                    new Random(39).NextBoolean());
 
                 // Assert
                 var exception = Assert.Throws<AssemblyException>(call);
@@ -534,7 +562,7 @@
         public void AssembleFailureMechanism_FailureMechanismNull_ThrowsArgumentNullException()
         {
             // Call
-            TestDelegate call = () => DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(null);
+            TestDelegate call = () => DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(null, new Random(39).NextBoolean());
 
             // Assert
             var exception = Assert.Throws<ArgumentNullException>(call);
@@ -557,7 +585,7 @@
                 FailureMechanismAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismAssemblyCalculator;
 
                 // Call
-                DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(failureMechanism);
+                DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(failureMechanism, new Random(39).NextBoolean());
 
                 // Assert
                 FailureMechanismSectionAssemblyCategoryGroup assemblyCategory =
@@ -576,14 +604,14 @@
             };
 
             // Call
-            FailureMechanismAssemblyCategoryGroup category = DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(failureMechanism);
+            FailureMechanismAssemblyCategoryGroup category = DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(failureMechanism, new Random(39).NextBoolean());
 
             // Assert
             Assert.AreEqual(FailureMechanismAssemblyResultFactory.CreateNotApplicableCategory(), category);
         }
 
         [Test]
-        public void AssembleFailureMechanism_WithManualInput_SetsInputOnCalculator()
+        public void AssembleFailureMechanism_WithManualInputAndUseManualTrue_SetsInputOnCalculator()
         {
             // Setup
             var failureMechanism = new DuneErosionFailureMechanism();
@@ -601,14 +629,42 @@
                 FailureMechanismAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismAssemblyCalculator;
 
                 // Call
-                DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(failureMechanism);
+                DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(failureMechanism, true);
 
                 // Assert
                 Assert.AreEqual(sectionResult.ManualAssemblyCategoryGroup, calculator.FailureMechanismSectionCategories.Single());
             }
         }
 
         [Test]
+        public void AssembleFailureMechanism_WithManualInputAndUseManualFalse_SetsNoInputOnCalculator()
+        {
+            // Setup
+            var failureMechanism = new DuneErosionFailureMechanism();
+            FailureMechanismTestHelper.SetSections(failureMechanism, new[]
+            {
+                FailureMechanismSectionTestFactory.CreateFailureMechanismSection()
+            });
+            DuneErosionFailureMechanismSectionResult sectionResult = failureMechanism.SectionResults.Single();
+            sectionResult.UseManualAssemblyCategoryGroup = true;
+            sectionResult.ManualAssemblyCategoryGroup = FailureMechanismSectionAssemblyCategoryGroup.IIv;
+
+            using (new AssemblyToolCalculatorFactoryConfig())
+            {
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismAssemblyCalculator;
+
+                // Call
+                DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(failureMechanism, false);
+
+                // Assert
+                FailureMechanismSectionAssemblyCategoryGroup expectedAssembly = DuneErosionFailureMechanismAssemblyFactory.AssembleCombinedAssessment(
+                    failureMechanism.SectionResults.Single());
+                Assert.AreEqual(expectedAssembly, calculator.FailureMechanismSectionCategories.Single());
+            }
+        }
+
+        [Test]
         public void AssembleFailureMechanism_AssemblyRan_ReturnsOutput()
         {
             // Setup
@@ -619,7 +675,8 @@
 
                 // Call
                 FailureMechanismAssemblyCategoryGroup actualOutput =
-                    DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(new DuneErosionFailureMechanism());
+                    DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(new DuneErosionFailureMechanism(),
+                                                                                        new Random(39).NextBoolean());
 
                 // Assert
                 Assert.AreEqual(calculator.FailureMechanismAssemblyCategoryGroupOutput, actualOutput);
@@ -632,12 +689,14 @@
             // Setup
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismAssemblyCalculator;
                 calculator.ThrowExceptionOnCalculate = true;
 
                 // Call
-                TestDelegate call = () => DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(new DuneErosionFailureMechanism());
+                TestDelegate call = () => DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(
+                    new DuneErosionFailureMechanism(),
+                    new Random(39).NextBoolean());
 
                 // Assert
                 var exception = Assert.Throws<AssemblyException>(call);
@@ -659,12 +718,13 @@
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
-                var calculatorfactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
-                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorfactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
                 calculator.ThrowExceptionOnCalculate = true;
 
                 // Call
-                TestDelegate call = () => DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(failureMechanism);
+                TestDelegate call = () => DuneErosionFailureMechanismAssemblyFactory.AssembleFailureMechanism(failureMechanism,
+                                                                                                              new Random(39).NextBoolean());
 
                 // Assert
                 var exception = Assert.Throws<AssemblyException>(call);