A ->good<- club girl will have much more than 8, providing that she has enough customers. Lvl 14 girl with 50 charisma/refinement/service will have 50-150 per shift depending on the number of customers and AP. And 14 is not even close to really high levels.
Basically, I don't want bad whores/waitresses/etc with 0-10 stats to be good, self-sustaining workers. You have to train them or find and convince to join some good ones (when we finally will have levels in girls data files).
Also, since only whores have such a thing as ranks, they should make the best profit, and they do even now.