During Counting, the amount of each type in the loaded Entity list should be counted when counting entities for type. If its higher than the Entity specific cap, it would exit as if the entity could not be spawned.

If performance was ever a concern, CreatureType may need to implement a Cache that's refreshed on the order of seconds (or every X cycles). Though since the discussion on Entity cache for the vanilla system this shouldn't cost that much more. A global toggle to disable creatureSpecific caps would likely be a better compromise for those it would be a problem for.