I mark down my prices depending on the pre-estimated amount of business they may give me. The maximum amount I mark down is 20% off. BE CAREFUL....alot of business coming from body shops will be busted up vehicles (unbelievable grime and dirt on the paint, broken glass & tons of dirt in the interior, foul smells, super dirty windows, and more), so make sure you let them know before hand that there will be an upcharge in fee for vehicles in very bad condition. But, from my experience body shop business is an excellent addition to a detailing company given that they typically do keep business coming to you. This is especially a very good thing during the current season up here in the north!
Good luck.:up