I have a 2006 300C. I see a lot of ads for the Chrysler oil change coupons at various prices (7 year, 28 coupons, every 3,000 miles). Do these coupons cover the oil, filter and labor completely? Are they really honored at all Chrysler dealers? I was quoted a very high price for a single oil and filter change at one dealer. I can't see how anyone can honor these coupons at the low prices quoted. Has anyone had any experiences, good or bad, using them? Thanks, regards, Bob.