There is no VW 15,000 mile service for US models. If you look in your owners booklets, there is one for scheduled maintenance and there is nothing for 15K. The dealer at the 10K is supposed to reset the reminder to go off evry 10K. If your dealer is doing what mine is, they are trying to drum up extra business. My dealer told me this is a way to monitor oil useage as VWs have been known for oil consumption figures. They consider 1 quart per 1k miles normal. But think about it. If the car uses a quart every thousand miles, by the time you take the car in there would be none left in the engine. My suggestion is to reset the reminder (info is in the O/M) and check your oil level regularly. Pick up a quart of oil and keep it in the trunk. In the US the two main oils used are Castrol Syntec 5W-40 and Mobil1 0W-40. Both are VW 502.00 approved and used by the dealers.