Hi Adi,

Sign Max Gives SIGNED value with maximum value.
Sign Min Gives SIGNED value with minimum value.

There is no doubt about the above said.
Say we have for the selected cases following forces at the restraints in X direction.

-250
-175
+150
+75

For SIGNMAX it should yield +150 (actual max value on number line)
For SIGNMIN it should yield -250 (actual min value on number line)

Whereas Max will give -250 (because it does not think about sign, only magnitude is considered, however while listing, it will be listed with sign)
&
Min will give +75

You can try out with some model.

Regards
Montek