My brother in law and a friend of 30 years started with an MB dealership about five years or so ago. He was a 25 year experienced, top notch truck mechanic with ASE Master, Cummins, Cat, etc. certifications. He said that none of those credentials meant ANYTHING to the MB dealer, they didn't want to hear about them.
It was, however, obvious to them that this was someone who could learn. He started as a B Tech and was an A in about a year I think.
I believe that if you have obvious credentials and experience then the rest depends upon their need for a tech and the "chemistry" between you and the hiring manager.
Best of luck,