And as I noted in that thread, this template is in the same book that gives advice on ad-hoccing LA. It's probably best to presume that if you put it to use, your DM will give you an ad-hoc LA based on a discussion you have with him on your particular pairing.
The +1 LA accounts for that. Unless you are going for some Incarnate Construct negative LA, the combined LA of the Creatures should cover it.
All gaming systems should be terribly flawed and exploitable if you want everyone to be happy with them. This allows for a wide variety of power levels for games for different levels of players.