I don't have a clue to fixing your problem, but this is addressed to the MBUSA people that lurk on this list. I'm betting you can make this guy happy real quick and keep this from getting out of hand. Of course, you could play like GM and figure you don't need to keep people happy with the impressive numbers you've been posting on sales.
So why not get it right the first time and calibrate the dealer while you're at it? I'd like to think you've got a better operation than GM or Toyota.