Mobil 1 does come in a couple of different grades.
The 10w60 is for "motor sport".
The one we normally refer to as "Mobil 1" is the 0w40 - normal road use, it meets all MB specs.
There are any number of other makes that meet these specs and MB do list them but Mobil 1 is a top quality oil. I have used it for years on a number of cars, it seems to last better than other full-synths, and preserves the engine well. I got over 330k out of the Volvo 245 before we parted company, engine still good.
The MB dash warning seems to come on when it wants 1 Litre of oil (mine actually states the amount to be put in).