Index: Ringtoets/Integration/src/Ringtoets.Integration.Data/AssessmentSection.cs
===================================================================
diff -u -r51e98f5938f7444882dcfd65fa2254b0fe32a3be -re9676ff582c6fef41c740b880e5161d581bde497
--- Ringtoets/Integration/src/Ringtoets.Integration.Data/AssessmentSection.cs	(.../AssessmentSection.cs)	(revision 51e98f5938f7444882dcfd65fa2254b0fe32a3be)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Data/AssessmentSection.cs	(.../AssessmentSection.cs)	(revision e9676ff582c6fef41c740b880e5161d581bde497)
@@ -697,7 +697,7 @@
         /// is not equal to the contribution of <paramref name="oldFailureMechanism"/>.</exception>
         private static void ValidateContribution(IFailureMechanism oldFailureMechanism, IFailureMechanism newFailureMechanism)
         {
-            if (!(Math.Abs(oldFailureMechanism.Contribution - newFailureMechanism.Contribution) < double.Epsilon))
+            if (Math.Abs(oldFailureMechanism.Contribution - newFailureMechanism.Contribution) >= double.Epsilon)
             {
                 throw new ArgumentException(Resources.AssessmentSection_ValidateContribution_Contribution_new_FailureMechanism_must_be_equal_to_old_FailureMechanism);
             }