I can't confirm a service A, or B difference in FSS, but my car's system doesn't recognize the difference, so I don't think this is an issue.
I reset the service couple times on my cars (ML and E-class, what is the same system) and what most of the posted instruction fail to mention is, that you have to start the procedure in "sleep mode". I corrected it several times on different MB forum and the error gets reposted over and over again.
This time I checked out some members experience of reseting with door open. It worked for me, but it takes longer for the car to go into sleep mode with door open, or at least that was my impression.
Timing is critical in the procedure. Even I did it couple times in the past, it took 3 tries this time to succeed. You have to act fast.