Quote Originally Posted by ReloadPsi View Post
Those six stats that can be augmented by Sources can go up to 255, although for some reason they may stop working when it reaches about 252 or 253. Don't ask me why, I just don't know :P
The base stats are capped at 255, and from there are then affected by materia negativity bonuses. So the 253 would be the result of having a materia with -2 to that stat. Also note that although negative stats worh on 255 values to bring them down, positive values won't raise them above (in other words, 255 is the max you'll ever get).