Index: Application/Ringtoets/src/Application.Ringtoets.Migration.Core/EmbeddedResources/Migration_17.3_18.1.sql
===================================================================
diff -u -rd9567ad9a530beced57fa695be79dbfba404d5fd -rd46a891e1b44443392e77b1f84224c89e1ec8785
--- Application/Ringtoets/src/Application.Ringtoets.Migration.Core/EmbeddedResources/Migration_17.3_18.1.sql	(.../Migration_17.3_18.1.sql)	(revision d9567ad9a530beced57fa695be79dbfba404d5fd)
+++ Application/Ringtoets/src/Application.Ringtoets.Migration.Core/EmbeddedResources/Migration_17.3_18.1.sql	(.../Migration_17.3_18.1.sql)	(revision d46a891e1b44443392e77b1f84224c89e1ec8785)
@@ -818,19 +818,23 @@
 );
 
 -- Create the calculations for the Hydraulic Boundary Locations on Grass Cover Erosion Outwards Failure Mechanism level
--- Note: it is assumed that the HBL entities of the grass cover erosion outwards failure mechanism have the same PK value 
--- as the HBL entities on assessment section level. Otherwise a join needs to be done on each column to find matching results
+-- Note 1: It is assumed that LocationId is unique within an assessment section. Because it is possible for multiple 
+-- assessment sections to have the same hydraulic boundary locations (and thus same LocationIds), a join needs to be 
+-- performed based on the LocationId and the AssessmentSection
+-- Note 2: The Hydraulic Location ID on assessment section level is chosen as a reference, because the hydraulic boundary 
+-- location calculation entities contain references to these entities.  
 INSERT INTO TempHydraulicLocationCalculationEntity (
 	[HydraulicLocationEntityId],
 	[GrassCoverErosionOutwardsFailureMechanismMetaEntityId],
 	[CalculationType])
 SELECT
-	[GrassCoverErosionOutwardsHydraulicLocationEntityId],
+	hl.HydraulicLocationEntityId,
 	[GrassCoverErosionOutwardsFailureMechanismMetaEntityId], 
 	[CalculationType]
-FROM [SOURCEPROJECT].GrassCoverErosionOutwardsHydraulicLocationEntity
-JOIN [SOURCEPROJECT].FailureMechanismEntity USING(FailureMechanismEntityId)
+FROM [SOURCEPROJECT].GrassCoverErosionOutwardsHydraulicLocationEntity gceohl
+JOIN [SOURCEPROJECT].FailureMechanismEntity fm USING(FailureMechanismEntityId)
 JOIN [SOURCEPROJECT].GrassCoverErosionOutwardsFailureMechanismMetaEntity USING(FailureMechanismEntityId)
+JOIN [SOURCEPROJECT].HydraulicLocationEntity hl ON (hl.LocationId = gceohl.LocationId AND hl.AssessmentSectionEntityId = fm.AssessmentSectionEntityId)
 JOIN (
 	SELECT * 
 	FROM TempCalculationTypes
@@ -1080,13 +1084,13 @@
 		JOIN HydraulicLocationCalculationEntity USING(HydraulicLocationCalculationCollectionEntityId)
 		JOIN HydraulicLocationEntity hl USING(HydraulicLocationEntityId)
 		JOIN (
-				SELECT 
-					LocationId,
-					AssessmentSectionEntityId,
-					ShouldDesignWaterLevelIllustrationPointsBeCalculated,
-					ShouldWaveHeightIllustrationPointsBeCalculated
-				FROM [SOURCEPROJECT].GrassCoverErosionOutwardsHydraulicLocationEntity
-				JOIN [SOURCEPROJECT].FailureMechanismEntity USING(FailureMechanismEntityId)
+			SELECT 
+				[LocationId],
+				[AssessmentSectionEntityId],
+				[ShouldDesignWaterLevelIllustrationPointsBeCalculated],
+				[ShouldWaveHeightIllustrationPointsBeCalculated]
+			FROM [SOURCEPROJECT].GrassCoverErosionOutwardsHydraulicLocationEntity
+			JOIN [SOURCEPROJECT].FailureMechanismEntity USING(FailureMechanismEntityId)
 		) SOURCE ON (SOURCE.LocationId = hl.LocationId AND SOURCE.AssessmentSectionEntityId = fm.AssessmentSectionEntityId)
 		WHERE (ShouldDesignWaterLevelIllustrationPointsBeCalculated = 1 AND NormativeNormType = 2 AND gceofmme.HydraulicLocationCalculationCollectionEntity2Id = hlcce.HydraulicLocationCalculationCollectionEntityId)
 		OR (ShouldDesignWaterLevelIllustrationPointsBeCalculated = 1 AND NormativeNormType = 1 AND gceofmme.HydraulicLocationCalculationCollectionEntity3Id = hlcce.HydraulicLocationCalculationCollectionEntityId)
@@ -1114,16 +1118,31 @@
 	[CalculatedReliability],
 	[CalculationConvergence]
 FROM GrassCoverErosionOutwardsFailureMechanismMetaEntity gceofmme
-JOIN FailureMechanismEntity USING(FailureMechanismEntityId)
+JOIN FailureMechanismEntity fm USING(FailureMechanismEntityId)
 JOIN AssessmentSectionEntity USING(AssessmentSectionEntityId)
 JOIN HydraulicLocationCalculationCollectionEntity hlcce 
 ON gceofmme.HydraulicLocationCalculationCollectionEntity2Id = hlcce.HydraulicLocationCalculationCollectionEntityId
 OR gceofmme.HydraulicLocationCalculationCollectionEntity3Id = hlcce.HydraulicLocationCalculationCollectionEntityId 
 OR gceofmme.HydraulicLocationCalculationCollectionEntity5Id = hlcce.HydraulicLocationCalculationCollectionEntityId 
 OR gceofmme.HydraulicLocationCalculationCollectionEntity6Id = hlcce.HydraulicLocationCalculationCollectionEntityId
 JOIN HydraulicLocationCalculationEntity USING(HydraulicLocationCalculationCollectionEntityId)
-JOIN [SOURCEPROJECT].GrassCoverErosionOutwardsHydraulicLocationEntity ON GrassCoverErosionOutwardsHydraulicLocationEntityId = HydraulicLocationEntityId
-JOIN [SOURCEPROJECT].GrassCoverErosionOutwardsHydraulicLocationOutputEntity USING(GrassCoverErosionOutwardsHydraulicLocationEntityId)
+JOIN HydraulicLocationEntity hl USING(HydraulicLocationEntityId)
+JOIN (
+	SELECT 
+		[LocationId],
+		[AssessmentSectionEntityId],
+		[GeneralResultSubMechanismIllustrationPointEntityId],
+		[Result],
+		[TargetProbability],
+		[TargetReliability],
+		[CalculatedProbability],
+		[CalculatedReliability],
+		[CalculationConvergence],
+		[HydraulicLocationOutputType]
+	FROM [SOURCEPROJECT].GrassCoverErosionOutwardsHydraulicLocationOutputEntity
+	JOIN [SOURCEPROJECT].GrassCoverErosionOutwardsHydraulicLocationEntity USING(GrassCoverErosionOutwardsHydraulicLocationEntityId)
+	JOIN [SOURCEPROJECT].FailureMechanismEntity USING(FailureMechanismEntityId)
+) SOURCE ON (SOURCE.LocationId = hl.LocationId AND SOURCE.AssessmentSectionEntityId = fm.AssessmentSectionEntityId)
 WHERE (HydraulicLocationOutputType = 1 AND NormativeNormType = 2 AND gceofmme.HydraulicLocationCalculationCollectionEntity2Id = hlcce.HydraulicLocationCalculationCollectionEntityId)
 OR (HydraulicLocationOutputType = 1 AND NormativeNormType = 1 AND gceofmme.HydraulicLocationCalculationCollectionEntity3Id = hlcce.HydraulicLocationCalculationCollectionEntityId)
 OR (HydraulicLocationOutputType = 2 AND NormativeNormType = 2 AND gceofmme.HydraulicLocationCalculationCollectionEntity5Id = hlcce.HydraulicLocationCalculationCollectionEntityId)
Index: Application/Ringtoets/test/Application.Ringtoets.Migration.Core.Test/test-data/FullTestProject173.rtd
===================================================================
diff -u -rd9567ad9a530beced57fa695be79dbfba404d5fd -rd46a891e1b44443392e77b1f84224c89e1ec8785
Binary files differ
Index: Application/Ringtoets/test/Application.Ringtoets.Migration.Core.Test/test-data/FullTestProject181.rtd
===================================================================
diff -u -r7581847b1a3f63af059c6ac976f14d6ec842e8cd -rd46a891e1b44443392e77b1f84224c89e1ec8785
Binary files differ
Index: Application/Ringtoets/test/Application.Ringtoets.Storage.Test/IntegrationTests/MigrationTo181IntegrationTest.cs
===================================================================
diff -u -rd9567ad9a530beced57fa695be79dbfba404d5fd -rd46a891e1b44443392e77b1f84224c89e1ec8785
--- Application/Ringtoets/test/Application.Ringtoets.Storage.Test/IntegrationTests/MigrationTo181IntegrationTest.cs	(.../MigrationTo181IntegrationTest.cs)	(revision d9567ad9a530beced57fa695be79dbfba404d5fd)
+++ Application/Ringtoets/test/Application.Ringtoets.Storage.Test/IntegrationTests/MigrationTo181IntegrationTest.cs	(.../MigrationTo181IntegrationTest.cs)	(revision d46a891e1b44443392e77b1f84224c89e1ec8785)
@@ -1767,16 +1767,34 @@
 
             private static string GetHydraulicLocationCalculationsFromFailureMechanismQuery(CalculationType calculationType)
             {
-                return "FROM GrassCoverErosionOutwardsFailureMechanismMetaEntity " +
+                return "FROM GrassCoverErosionOutwardsFailureMechanismMetaEntity gceofmm " +
                        "JOIN HydraulicLocationCalculationCollectionEntity " +
-                       $"ON HydraulicLocationCalculationCollectionEntity{(int) calculationType}Id = HydraulicLocationCalculationCollectionEntityId " +
-                       "JOIN HydraulicLocationCalculationEntity USING(HydraulicLocationCalculationCollectionEntityId) ";
+                       $"ON gceofmm.HydraulicLocationCalculationCollectionEntity{(int) calculationType}Id = HydraulicLocationCalculationCollectionEntityId " +
+                       "JOIN HydraulicLocationCalculationEntity USING(HydraulicLocationCalculationCollectionEntityId) " +
+                       "JOIN HydraulicLocationEntity hl USING(HydraulicLocationEntityId) " +
+                       "JOIN FailureMechanismEntity fm USING(FailureMechanismEntityId) " +
+                       "JOIN AssessmentSectionEntity USING(AssessmentSectionEntityId) ";
             }
 
             private static string GetHydraulicLocationCalculationOutputValidationSubQuery()
             {
                 return "JOIN HydraulicLocationOutputEntity NEW USING(HydraulicLocationCalculationEntityId) " +
-                       "JOIN [SOURCEPROJECT].GrassCoverErosionOutwardsHydraulicLocationOutputEntity OLD ON NEW.GeneralResultSubMechanismIllustrationPointEntityId IS OLD.GeneralResultSubMechanismIllustrationPointEntityId " +
+                       "JOIN ( " +
+                       "SELECT " +
+                       "LocationId, " +
+                       "AssessmentSectionEntityId, " +
+                       "GeneralResultSubMechanismIllustrationPointEntityId, " +
+                       "Result,  " +
+                       "TargetProbability, " +
+                       "TargetReliability, " +
+                       "CalculatedProbability, " +
+                       "CalculatedReliability, " +
+                       "CalculationConvergence " +
+                       "FROM [SOURCEPROJECT].GrassCoverErosionOutwardsHydraulicLocationOutputEntity " +
+                       "JOIN [SOURCEPROJECT].GrassCoverErosionOutwardsHydraulicLocationEntity USING(GrassCoverErosionOutwardsHydraulicLocationEntityId) " +
+                       "JOIN [SOURCEPROJECT].FailureMechanismEntity USING(FailureMechanismEntityId) " +
+                       ") OLD ON (fm.AssessmentSectionEntityId = OLD.AssessmentSectionEntityId AND OLD.LocationId = hl.LocationId)" +
+                       "WHERE NEW.GeneralResultSubMechanismIllustrationPointEntityId IS OLD.GeneralResultSubMechanismIllustrationPointEntityId " +
                        "AND NEW.Result IS OLD.Result " +
                        "AND NEW.TargetProbability IS OLD.TargetProbability " +
                        "AND NEW.TargetReliability IS OLD.TargetReliability " +