"Wait, that didn't work right" - the Dysfunctional Rules Collection

[tyckspoon]

Actually, that rule is generally disregarded entirely. If you were to apply it, there is no basis to apply it selectively, because it doesn't specify "the prestige classes in this book."

Actually, Primary Source applies here. The DMG is primary source for how prestige classes work. Unless another book specifically over-rules that, like how Spell Compendium and Magic Item Compendium specifically are the definitive new rules for the stuff in there, then any new rules about Prestige Classes can only apply to the book those rules came from- everything else refers either to itself or to the DMG if no specific rules are given.

Edit: As distinct from the Weapon-like spells rules, which are generally applied because the core books don't tell you how to deal with those.