diff --git a/Source/Plugins/BuilderModes/VisualModes/VisualSidedefSlope.cs b/Source/Plugins/BuilderModes/VisualModes/VisualSidedefSlope.cs
index 6346c914..b6c2c38d 100644
--- a/Source/Plugins/BuilderModes/VisualModes/VisualSidedefSlope.cs
+++ b/Source/Plugins/BuilderModes/VisualModes/VisualSidedefSlope.cs
@@ -315,14 +315,10 @@ namespace CodeImp.DoomBuilder.VisualModes
 			Plane originalplane = level.plane;
 			Plane pivotplane = ((VisualSidedefSlope)pivothandle).Level.plane;
 
-			// Build a new plane. p1 and p2 are the points of the slope handle that is modified, p3 is on the line of the pivot handle
-			Vector3D p1 = new Vector3D(sidedef.Line.Start.Position, Math.Round(originalplane.GetZ(sidedef.Line.Start.Position)));
-			Vector3D p2 = new Vector3D(sidedef.Line.End.Position, Math.Round(originalplane.GetZ(sidedef.Line.End.Position)));
-			Vector3D p3 = new Vector3D(((VisualSidedefSlope)pivothandle).Sidedef.Line.Line.GetCoordinatesAt(0.5f), Math.Round(pivotplane.GetZ(((VisualSidedefSlope)pivothandle).Sidedef.Line.Line.GetCoordinatesAt(0.5f))));
-
-			// Move the points of the handle up/down
-			p1 += new Vector3D(0f, 0f, amount);
-			p2 += new Vector3D(0f, 0f, amount);
+			// Build a new plane. p1 and p2 are the points of the slope handle that is modified, with the changed amound added; p3 is on the line of the pivot handle
+			Vector3D p1 = new Vector3D(sidedef.Line.Start.Position, originalplane.GetZ(sidedef.Line.Start.Position) + amount);
+			Vector3D p2 = new Vector3D(sidedef.Line.End.Position, originalplane.GetZ(sidedef.Line.End.Position) + amount);
+			Vector3D p3 = new Vector3D(((VisualSidedefSlope)pivothandle).Sidedef.Line.Line.GetCoordinatesAt(0.5), pivotplane.GetZ(((VisualSidedefSlope)pivothandle).Sidedef.Line.Line.GetCoordinatesAt(0.5)));
 
 			Plane plane = new Plane(p1, p2, p3, true);