Now I know I'm behind here and I am aware of the time limit to keep us from spamming the bosses and am fine with it but I need to know one thing. What is the difference between using one and using multiple at once? I am of the impression that the "stackable" effect is when you use one and it does NOT give anything you get a bigger bonus next time but a friend of mine swears that multiple stack at one time. Which is it?