Guys - thanks for the input on the subject of traverse - i'll just read it through and digest those parts before returning with a response. FYI, I have calibrated my X Y Z steps and they seem to be more or less spot on at the moment.

I decided to do a simple pen test for a simple 50mm diameter circle.
-> I exported the .tap file (mach3 mill post processor) and ran it in Mach4.

Result: The circle drawn with the pen came out as 5mm and not 50mm.

Could this have something to do with the stepper drivers being set to 1/10th Microstep? (recommended setting from the provider for my Nema motors).
If so, how do I "normalize" this?