Just had my A6 in for a diagnosis of some problems and a spark plug change at dealer in CT. The prices quoted for parts and also labor were outrageous as compared to other dealers. In addition, I paid around $160 to replace 6 spark plugs and when I examined the engine later at home, found the spark plugs were never changed.
After confronting the Service manager with the car and unchanged plugs he gave me a refund! I'll be keeping far away from that dealership!
Hopefully you are all aware that service writers are usually on commission.