I am not a Mercedes technician. I do know that most auto techs work on a flat rate system. Hourly flat rates are published which provide guidance on how many hours a particular job will take. Most experienced techs earn 50% or more of the stated flat rate hours. The shop owner/dealer gets the other 50%. Depending on the location, flat rates range (the amount the customer pays) from $50 to $200 per hour. Most good techs are able to accomplish most jobs faster than the stated flat rate hours for a particular job, however, they are still paid for the published number of flat rate hours.