Index: Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsFailureMechanismAssemblyFactory.cs
===================================================================
diff -u -r8a84e69fe9834dc4bb5e3dd84240fb1de3a4280e -r879b557f344d372b856abef554d182ef6d264cda
--- Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsFailureMechanismAssemblyFactory.cs	(.../MacroStabilityInwardsFailureMechanismAssemblyFactory.cs)	(revision 8a84e69fe9834dc4bb5e3dd84240fb1de3a4280e)
+++ Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsFailureMechanismAssemblyFactory.cs	(.../MacroStabilityInwardsFailureMechanismAssemblyFactory.cs)	(revision 879b557f344d372b856abef554d182ef6d264cda)
@@ -30,6 +30,7 @@
 using Ringtoets.Common.Data.AssessmentSection;
 using Ringtoets.Common.Data.Exceptions;
 using Ringtoets.Common.Data.Probability;
+using Ringtoets.Common.Primitives;
 
 namespace Ringtoets.MacroStabilityInwards.Data
 {
@@ -213,19 +214,24 @@
                 throw new ArgumentNullException(nameof(assessmentSection));
             }
 
-            FailureMechanismSectionAssembly simpleAssembly = AssembleSimpleAssessment(failureMechanismSectionResult);
-            FailureMechanismSectionAssembly detailedAssembly = AssembleDetailedAssessment(
-                failureMechanismSectionResult, calculationScenarios, failureMechanism, assessmentSection);
-            FailureMechanismSectionAssembly tailorMadeAssembly = AssembleTailorMadeAssessment(
-                failureMechanismSectionResult, failureMechanism, assessmentSection);
-
             IAssemblyToolCalculatorFactory calculatorFactory = AssemblyToolCalculatorFactory.Instance;
             IFailureMechanismSectionAssemblyCalculator calculator =
                 calculatorFactory.CreateFailureMechanismSectionAssemblyCalculator(AssemblyToolKernelFactory.Instance);
 
             try
             {
-                return calculator.AssembleCombined(simpleAssembly, detailedAssembly, tailorMadeAssembly);
+                FailureMechanismSectionAssembly simpleAssembly = AssembleSimpleAssessment(failureMechanismSectionResult);
+
+                if (failureMechanismSectionResult.SimpleAssessmentResult == SimpleAssessmentResultType.ProbabilityNegligible ||
+                    failureMechanismSectionResult.SimpleAssessmentResult == SimpleAssessmentResultType.NotApplicable)
+                {
+                    return calculator.AssembleCombined(simpleAssembly);
+                }
+
+                return calculator.AssembleCombined(
+                    simpleAssembly,
+                    AssembleDetailedAssessment(failureMechanismSectionResult, calculationScenarios, failureMechanism, assessmentSection),
+                    AssembleTailorMadeAssessment(failureMechanismSectionResult, failureMechanism, assessmentSection));
             }
             catch (FailureMechanismSectionAssemblyCalculatorException e)
             {
Index: Ringtoets/MacroStabilityInwards/test/Ringtoets.MacroStabilityInwards.Data.Test/MacroStabilityInwardsFailureMechanismAssemblyFactoryTest.cs
===================================================================
diff -u -r1ccc4cae6b203b1f7791833ab1ad0bcba0a9757f -r879b557f344d372b856abef554d182ef6d264cda
--- Ringtoets/MacroStabilityInwards/test/Ringtoets.MacroStabilityInwards.Data.Test/MacroStabilityInwardsFailureMechanismAssemblyFactoryTest.cs	(.../MacroStabilityInwardsFailureMechanismAssemblyFactoryTest.cs)	(revision 1ccc4cae6b203b1f7791833ab1ad0bcba0a9757f)
+++ Ringtoets/MacroStabilityInwards/test/Ringtoets.MacroStabilityInwards.Data.Test/MacroStabilityInwardsFailureMechanismAssemblyFactoryTest.cs	(.../MacroStabilityInwardsFailureMechanismAssemblyFactoryTest.cs)	(revision 879b557f344d372b856abef554d182ef6d264cda)
@@ -579,7 +579,9 @@
         }
 
         [Test]
-        public void AssembleCombinedAssessment_WithInput_SetsInputOnCalculator()
+        [TestCase(SimpleAssessmentResultType.None)]
+        [TestCase(SimpleAssessmentResultType.AssessFurther)]
+        public void AssembleCombinedAssessment_WithInputSimpleAssemblyNoneOrAssessFurther_SetsInputOnCalculator(SimpleAssessmentResultType simpleAssessmentResult)
         {
             // Setup
             var failureMechanism = new MacroStabilityInwardsFailureMechanism();
@@ -588,7 +590,10 @@
             IAssessmentSection assessmentSection = AssessmentSectionHelper.CreateAssessmentSectionStub(failureMechanism, mocks);
             mocks.ReplayAll();
 
-            var sectionResult = new MacroStabilityInwardsFailureMechanismSectionResult(FailureMechanismSectionTestFactory.CreateFailureMechanismSection());
+            var sectionResult = new MacroStabilityInwardsFailureMechanismSectionResult(FailureMechanismSectionTestFactory.CreateFailureMechanismSection())
+            {
+                SimpleAssessmentResult = simpleAssessmentResult
+            };
 
             using (new AssemblyToolCalculatorFactoryConfig())
             {
@@ -623,6 +628,47 @@
         }
 
         [Test]
+        [TestCase(SimpleAssessmentResultType.NotApplicable)]
+        [TestCase(SimpleAssessmentResultType.ProbabilityNegligible)]
+        public void AssembleCombinedAssessment_WithInputSimpleAssemblyNotApplicableOrProbabilityNegligible_SetsInputOnCalculator(
+            SimpleAssessmentResultType simpleAssessmentResult)
+        {
+            // Setup
+            var failureMechanism = new MacroStabilityInwardsFailureMechanism();
+
+            var mocks = new MockRepository();
+            IAssessmentSection assessmentSection = AssessmentSectionHelper.CreateAssessmentSectionStub(failureMechanism, mocks);
+            mocks.ReplayAll();
+
+            var sectionResult = new MacroStabilityInwardsFailureMechanismSectionResult(FailureMechanismSectionTestFactory.CreateFailureMechanismSection())
+            {
+                SimpleAssessmentResult = simpleAssessmentResult
+            };
+
+            using (new AssemblyToolCalculatorFactoryConfig())
+            {
+                var calculatorFactory = (TestAssemblyToolCalculatorFactory) AssemblyToolCalculatorFactory.Instance;
+                FailureMechanismSectionAssemblyCalculatorStub calculator = calculatorFactory.LastCreatedFailureMechanismSectionAssemblyCalculator;
+
+                // Call
+                MacroStabilityInwardsFailureMechanismAssemblyFactory.AssembleCombinedAssessment(
+                    sectionResult,
+                    Enumerable.Empty<MacroStabilityInwardsCalculationScenario>(),
+                    failureMechanism,
+                    assessmentSection);
+
+                // Assert
+                FailureMechanismSectionAssembly expectedSimpleAssembly = MacroStabilityInwardsFailureMechanismAssemblyFactory.AssembleSimpleAssessment(
+                    sectionResult);
+
+                AssemblyToolTestHelper.AssertAreEqual(expectedSimpleAssembly, calculator.CombinedSimpleAssemblyInput);
+                Assert.IsNull(calculator.CombinedDetailedAssemblyInput);
+                Assert.IsNull(calculator.CombinedTailorMadeAssemblyInput);
+                mocks.VerifyAll();
+            }
+        }
+
+        [Test]
         public void AssembleCombinedAssessment_AssemblyRan_ReturnsOutput()
         {
             // Setup