there was as an investigation done here in Canada, several different dealers and brands, on an news channel. The advice given by service advisors generally is quite different than what the manual says. After the service advisor would give a long list of things to do, it was compared to what the owners manual says. They do try to get you in as much as possible because they make mucho money on the upsell of things on a service visit. Not much profit on an oil change, as example, but while you are there, hey you need this, time to change this fluid, and this, and that.. to drive up profits. for years now I have not been to the dealer, I change my own oil, follow the manual. most fluids I can do myself.