Nope, I tried it before. Like example from lvl 31-32 u need 14k exp then u changed it from 50 to 25, then to 32-33 u would need 17,5k then you changed it again to 50 then 33-34 would need 26250. Players will be upset with the current exp they got from monsters because, when you changed to 25% they feel easier to leveling and when you change back and the exp cap is rising but the exp stay the same.