Prices are interesting, but if the car is 4 years old it should be a B Service on the basis that A and B alternate every 12 months. Have you run the car through MB ESS? The ATf is due at 3 years or 30k miles, but at four years there are extras so the price you have to check is service plus extras. Some good discounting on MB My Service site too, check out my other threads. I just had my service which was a B3 according to the car and correlated to MB ESS.
Kamal
The car was 1st reg in Oct 2008 and is indicating an AO service is due with 21K miles.