It's tough because I don't think you can excuse the fact that some dealer's try to overcharge. However on the same token I can see that in order to provide a 10 year warranty, you need to expect that your drivers are regularly servicing their cars at the appropriate intervals by the right people.

At the end of the day, you don't actually need to abide by the warranty and you can still have your standard warranty period if you don't follow the rules.