Quote Originally Posted by bid View Post
Anything in the Classes chapter uses class level, as it assumes you are single-classed.
MC assumes you use each of your classes features independently and separately, as if your other class levels didn't exist.

Maybe you want your wizard 1 / cleric 16 to cast wish, but it's a big no-no.
A load if nonsense. If the designers meant warlock level, they would have said that. For clarification, see the paladin lay on hands ability and the cleric's divine intervention ability.