Not to imply that I'm "a bit better", (Hood RULES),

just thought I'd chuck this in.
Looks like some systems use arcs to enter and exit the offset amount of "I". I guess that's the extra variables.
Mach doesn't seem to support this method. Like Hood said, Mach just offsets the X axis the amount of "I", then cuts the circular path.
It's really not much different than G2 or G3 if it doesn't include the lead in/out arcs.
It only cuts a pocket if the offset is <= the cutter dia. or if you make multiple passes increasing the offset each time.
Good for counterbores.
I read about this earlier on the zone.
May or may not be true, I haven't tried it yet.
RC
The Z0.5 move in line 5 looks out of place too. ? ?