Also, I think having semi-randomized results with estimates for promotions, performances and spa treatments could add a little more realism to the game. For example: A Lv. 1 Performance, instead of always yielding a 10k profit, could yield a random amount of yens between, say, 1k and 20k. For Promotions, instead of always getting 7 fans, maybe work with a random number between 1 and 15. For Spa Treatment, between 5 and 15 stamina points. Of course, as the player levels up those activities, the values also go up.
The system would work similarly to World Tours, SIngles and Concerts, for example, that also work with estimated values. Not sure how much luck is involved there, but the thing is there's no surefire way to know exactly how many fans you'll get from promoting your group, or how much money a performance will add to your pockets, and I feel IM could benefit from reflecting those real life conditions in-game.