Index: Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Service/MacroStabilityInwardsCalculationService.cs
===================================================================
diff -u -r1bb88ae89a19c2213d616243bca2a3a6326c5612 -r966dc7335defa901104fd4168d57c08315db2de0
--- Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Service/MacroStabilityInwardsCalculationService.cs	(.../MacroStabilityInwardsCalculationService.cs)	(revision 1bb88ae89a19c2213d616243bca2a3a6326c5612)
+++ Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Service/MacroStabilityInwardsCalculationService.cs	(.../MacroStabilityInwardsCalculationService.cs)	(revision 966dc7335defa901104fd4168d57c08315db2de0)
@@ -63,7 +63,9 @@
                 return false;
             }
 
-            List<string> validationResults = new MacroStabilityInwardsCalculator(CreateInputFromData(calculation.InputParameters), MacroStabilityInwardsSubCalculatorFactory.Instance).Validate();
+            MacroStabilityInwardsCalculatorInput macroStabilityInwardsCalculatorInput = CreateInputFromData(calculation.InputParameters);
+            IMacroStabilityInwardsCalculator calculator = MacroStabilityInwardsCalculatorFactory.Instance.CreateCalculator(macroStabilityInwardsCalculatorInput, MacroStabilityInwardsSubCalculatorFactory.Instance);
+            List<string> validationResults = calculator.Validate();
             CalculationServiceHelper.LogMessagesAsError(RingtoetsCommonServiceResources.Error_in_validation_0, validationResults.ToArray());
 
             CalculationServiceHelper.LogValidationEnd();
@@ -90,7 +92,8 @@
 
             try
             {
-                MacroStabilityInwardsCalculatorResult macroStabilityInwardsResult = new MacroStabilityInwardsCalculator(CreateInputFromData(calculation.InputParameters), MacroStabilityInwardsSubCalculatorFactory.Instance).Calculate();
+                IMacroStabilityInwardsCalculator calculator = MacroStabilityInwardsCalculatorFactory.Instance.CreateCalculator(CreateInputFromData(calculation.InputParameters), MacroStabilityInwardsSubCalculatorFactory.Instance);
+                MacroStabilityInwardsCalculatorResult macroStabilityInwardsResult = calculator.Calculate();
 
                 calculation.Output = new MacroStabilityInwardsOutput(new MacroStabilityInwardsOutput.ConstructionProperties
                 {