I bought and decided to try Combative Cinnamon booster, which promises "Get +5 Mojo on a win or lose 0 Mojo on a loss in Seasons for the next 100 performances". After six fights I haven't gotten any extra Mojos on a win, but have definitely lost Mojos on a loss.
So, did I get swindled by that old geezer at Shops or what's the problem?
EDIT: Okay, it started working after I logged off and then logged in again.