My first change had some similarities. In another post here, somewhere, but.

Got the change. On the way home, the oil light came on and then went back off. I tried to pretend it was the computer resetting itself, or something equally as normal.

When I got home and climbed out, the whole place reeked of burnt oil. Called the dealer, they assured me at the time they put in 7.5. After a huge snafu geting the car flat-bedded back to the dealership, and three weeks of it in there 'care' they never found anything wrong (that they admitted to, even though it wasn't "ready" for about two-and-a-half weeks). No spillage burns that they could find, oil at correct level, everything in place, etc,.

No problems since (though I was kind of hoping it would burn out there for a while). I have serious reservations about what to do when it needs its second change (another month, I estimate). I am thinking a Mercedes shop might be better suited to do this. But, I would recommend if you see the light flash after a change, stop and give the hood a good sniff, just incase.