Seal bonus

[Dudimus]

I've been playing that the seals give a plus to the combat, not the individual monsters, but looking over the rules, it seems rather ambiguous, and I wonder if I've been doing it wrong.

The rules says that "monsters" get the bonus, but doest that mean each monster, or the monsters as a group?

And does this bonus apply to monsters that have for some reason joined the munchkin side? (i.e. Rock of Repentance or a ranger taming it)