Eric The Red brings up a very good point. Virtually no non-oem labor time guide is based on any independant time studies, they all use the factory warranty times with a multiplier. And, at least in Ford's case, the warranty times have been being cut dramatically over the last couple of years, and the new (lower) times re-published for past model years. So if shop A uses a 4 year old Chilton's manual to price a job on a 1998 vehicle, and shop B uses a brand new Chilton's to price the same job on the same 1998 vehicle, the "new and improved" factory times may result in two very different labor times.