I was playing with the grid setting too and could not get it to work. Did it for you as I get a message that says "The mark size must be between 1 and 10." Tried all kinds of combinations with no luck. Using eCAL and not SCAL, but that shouldn't make a difference.
Close eCAL for the night and opened this morning and guess what....the grid changes were there. Guess closing and opening took care of it even though I got that error reading.