This oil leak or use is a warranty item, don't let a dealer tell you
that this is normal - it isn't.
A 10,000 Km car should use NO oil between changes. None.
Keep a record of oil additions and receipts for the oil, mark the Km
reading on each receipt so you have proof of the oil replacement and
give (copies) to dealer and MB. If they can't eliminate the oil leak /
use then they should install a new replacement engine.
I own a '97 E320 with 50,000 Km and an '80 300SD turbodiesel with
172,500 Km, neither uses any oil between regular oil changes. That's
what you should expect from your car, nothing less.