Index: Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Service/GrassCoverErosionInwardsCalculationService.cs
===================================================================
diff -u -re88fa1dfcf62085f7fabc453b73dbc8ac3ff9223 -re039612b6aedef09462b8f260b2f377483d4ea65
--- Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Service/GrassCoverErosionInwardsCalculationService.cs	(.../GrassCoverErosionInwardsCalculationService.cs)	(revision e88fa1dfcf62085f7fabc453b73dbc8ac3ff9223)
+++ Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Service/GrassCoverErosionInwardsCalculationService.cs	(.../GrassCoverErosionInwardsCalculationService.cs)	(revision e039612b6aedef09462b8f260b2f377483d4ea65)
@@ -104,15 +104,15 @@
         {
             for (var i = 0; i < roughnessProfilePoints.Count; i++)
             {
-                var roughnessProfilePoint = roughnessProfilePoints.ElementAt(i);
+                var roughnessProfilePoint = roughnessProfilePoints[i];
 
                 if (i == 0)
                 {
                     yield return new HydraRingRoughnessProfilePoint(roughnessProfilePoint.Point.X, roughnessProfilePoint.Point.Y, 1.0);
                 }
                 else
                 {
-                    var precedingRoughnessProfilePoint = roughnessProfilePoints.ElementAt(i - 1);
+                    var precedingRoughnessProfilePoint = roughnessProfilePoints[i - 1];
 
                     yield return new HydraRingRoughnessProfilePoint(roughnessProfilePoint.Point.X, roughnessProfilePoint.Point.Y, precedingRoughnessProfilePoint.Roughness);
                 }