Index: trunk/psLib/src/fits/psFitsScale.c
===================================================================
--- trunk/psLib/src/fits/psFitsScale.c	(revision 25383)
+++ trunk/psLib/src/fits/psFitsScale.c	(revision 25439)
@@ -319,7 +319,7 @@
                     value = (value - zero) * scale; \
                     if (options->fuzz) { \
-                       /* Add random factor [0,1): adds a variance of 1/12, */ \
+                       /* Add random factor [-0.5,0.5): adds a variance of 1/12, */ \
                        /* but preserves the expectation value */ \
-                        value += psRandomUniform(rng); \
+                        value += psRandomUniform(rng) - 0.5; \
                     } \
                     /* Check for underflow and overflow; set either to max */ \