Saw your pic on the other forum and I think your issue with the last turn being off pitch, is due to the slow acceleration that steppers have. Try setting a chamfer angle of maybe 360 or more and see. I am sure Grahame sorted the macro about 3 or so years ago so that the chamfer worked correctly, it should start pulling out at the value you set, ie 360 degrees before the last rotation, that should help things be cleaner at the end.
Hood