Hmmm... They probably get a special deal and don't pay the full amount....

I don't know about you guys but if I brought my car in and they replaced a 9k Part and did not do any further testing and driving and the problem ended up being a much cheaper part I don't think I would bring any of my cars back to that shop/dealership.... They seem more interested in moving vehicles in and out at the maximum profit rather than actually repairing them......

Perhaps your problem might be solved by going to a more experienced independant mechanic? The dealerships do have "factory training" but screw over mechanics in droves and can't seem to keep the good ones. I have found the best mechanics are not at the dealerships.