There are no 'advisory notes' on the Digital Service Book, so no one will know what the dealer told you needed doing (rightly or wrongly).
With regards MOT, yes advisories are a bummer, but that's just pot luck, in this respect MB dealers are no better or worse than any other MOT testing station.
My Suzuki had flawless MOT history, and this is what the Suzuki dealer did to it during the last MOT:
That unbelievably stupid... I complained to the service manager to no avail, I even called the DVLA who said that since the car passed there's nothing they can do, and the MOT testers have the right to put anything they want in the 'advisory notes' section.