The engines had a coating applied to the cylinder walls that (theoretically) reduce frinction. Turns out the coating was a bad decision (it wasn't throughly tested (see a pattern?)), and they rolled back to their old way of building engines (which was pretty good).
I do think the 10k is not a problem with Mobil 1 synthetic. I've used that oil for about 15k on my own cars without complications.
If you want to learn more about the engine problems, you might want to ddg the words "mercedes benz nikasil".