Oh, this bugged me when I was doing a real play-through earlier:
CheatMaster can only target the front row. Little confusing if you select a back row mob first.
Maybe you should disable EXP if CheatMaster is used during a fight. I have a feeling Solo Althea can easily top level 30 with this, and I don't know what'll happen? (Plus, you can get the grinder achievement.) You can also get the "This is our story" achievement, but that one is more for fun I think.