Question for GM, is it okay to assume that Charm always has the free invocation on for 8 temporary extra hit points or must she know a combat is coming to cast it and roll the 1d4+4. To try to persuade to treat as the first case, it can be cast every round she's not otherwise occupied so eventually she would get the roll she wanted for maximizing and it's an invocation for which she gave up the likes of Book of Ancient Secrets so it's supposed to be powerful. To counter myself, she's not the type that would worry or minimax unless her dark passenger controls her enough to keep it cast.