Changes

Generally, I've noticed that expending spells for class features tends to be pretty crappy the higher level spell you use. Offhand I can't think of any class feature where using a level 9 is that much better than a level 8, but I'm probably forgetting some class out there. Either way, this is an idea to "fix" that problem. It's a straight up buff for caster types, but it does encourage some previously crappy PrCs, likely.

When expending a spell slot to activate a class feature, its effective level for the purposes of "powering" the class feature, other than DCs, is determined by the following table: