SetVar(1, GetOEMDRO(800))
SetVar(2, GetOEMDRO(801))
SetVar(3, GetOEMDRO(802))
Somehow, I don't think the M6Start macro you have is the normal one distributed with Mach3. It suggests someone was playing all sorts of games at some stage, transferring the X, Y & Z DROs into #1, #2 & #3. I can see why one might do that while experimenting though.
A bit embarrassing if you were already using those variables for something else of course.
Cheers
Roger