Index: /trunk/psModules/src/imcombine/pmSubtractionKernels.c
===================================================================
--- /trunk/psModules/src/imcombine/pmSubtractionKernels.c	(revision 24295)
+++ /trunk/psModules/src/imcombine/pmSubtractionKernels.c	(revision 24296)
@@ -164,5 +164,5 @@
                     psBinaryOp(xKernel, xKernel, "*", psScalarAlloc(sum, PS_TYPE_F32));
                     psBinaryOp(yKernel, yKernel, "*", psScalarAlloc(sum, PS_TYPE_F32));
-                    moment *= sum;
+                    moment *= PS_SQR(sum);
                 }