I think this should be changed to 3 uses per day. It somehow should be lengthened, though I think by doubling or tripling the cha modified duration, you end up promoting less emphasis on the charisma, which is the source for the power. However, if you make it multiple uses per day, you don't really power up the class, you just help make it useful for a PW with rest limitations and generally low magic, which prevents maximizing all character stats in a fashion that maximized charisma for such feat useage was partly intended.
I feel like I've posted this before for some reason... if so... sorry for being a broken record.
