The dealer (Barrier) is charging well over $100/hr now.
Actually, the costs that your guy charged do not seem out of line for around here.
But he certainly didn't screw you. Mechanics have to charge list prices for parts...it's really the only way they can stay in business.
I have found a gem of a mechanic among common stones in the area. He is:
Mercedes Benz Service
Automeister II, Inc
mobile (866) 964-2886
work (425) 822-5708
12029 NE 85th Street
Kirkland WA 98033
One block east of Lee Johnson Chev on the same side of 85th tucked back in the corner of an auto strip mall.
You will not be disappointed.