Got new rotors - now the ABS kicks in all the time

After 200,000 miles, splurged for new rotors, pads, and a timing chain for the 420. The cars was running and braking fine.

Question: When I got the car back and did a test drive, the ABS system kicked in everytime I applied the brake a little harder than normal. Before the ABS kicked in only when I slammed on the brakes when I was on snow/ice, never would it kick in on dry pavement - never.

I called my Tech and he told me to bring it back in for probably some "Dust" got on the pads during installation and he has to clean the pads off. Does that sound right?

He also said that you don't bleed the brakes on Mercedes unless you absolutely have to. I was curious because the pedal was not that much firmer after the new rotors.

I called a dealer about the ABS kicking in after new rotors and he thought that was something that would go away with time after the pads get better contact with mileage.

I hope to get the car back today. Was wondering what you thought?