First let me say that after 24 years of Mercedes-Benz Dealership Parts
experience that in my humble opinion that there are few if any
"Qualified" independent repair shops as most don't have uptodate
factory training and probably none have the required test equipment
needed to properly diagnose the vehicles.

That being said here is a description of the service performed by a
recent employer Mercedes-Benz of Tampa 866-777-9545Service:
813-873-2360 Parts: 813-878-0040 4636 N Dale Mabry Hwy Tampa, FL 33614
on their website.

There are basicly only two types of services "A" and "B" with all
other letters being used to designate a "B" type service at least at
the above mentioned Dealership. So here it is:

Here is what we do:

◦Replace windshield wiper inserts and service windshield washer
system
◦Inspect and rotate tires, record tread depth, and correct tire
pressure (wheel balance additional) – Excludes AMG, Sports Models, SLK
and vehicles with staggered wheels
◦Engine oil change and oil filter replacement – Includes Mobile 1
synthetic oil
◦Lubrication service – Includes hood hinges, lock cylinders, striker
plates, sun roof tracks and a top-off of all fluids
◦Cooling system inspection – Includes antifreeze protection level,
hoses and clamps
◦Brake inspection – Includes checking pad thickness and condition of
discs, fluids and lines
◦Replace heating and ventilation dust filter – Dust filter prices vary
by model, please check with your Team Service Manager
◦Function check – Includes warning lamps, headlights, exterior lights,
seat belts, windshield wiper and washer
◦Inspect and lubricate throttle linkage
◦Replace air filter
◦Reset flexible service system counter
◦Inspect front axle ball joints; check steering play and power
steering clutch; and rear differential levels
◦Inspect Poly V-Belt for condition
◦Inspect starting and charging system, and service battery
◦Inspect climate control refrigerant

Here is why we do it:

During the B-Service, Certified Mercedes-Benz Technicians closely
examine your automobile’s engine components, using specialized
equipment to be sure that all the mechanical, electronic, and
computerized devices are functioning properly.

At this time, we also need to address your automobile’s heating and
cooling system. Over time, your engine coolant becomes contaminated,
losing its ability to protect your engine from freezing in cold
weather conditions and overheating in hot conditions. Very expensive
repairs could result from avoiding this required maintenance.

Next, we inspect your fuel lines and connectors for any damage or
wear, and we check your fuel tank vapor vent system, hoses and fuel
tank supports. As we said above on the A-Service, it’s important that
you trust only a Mercedes-Benz Factory Trained and Certified
Technician to perform these functions.

Prices are market specific and you should call your local Dealer for
that. Les