Thanks for replying, that sounds like a reasonable solution. I'm not able to check it, though, because my mill is out in the woods in offline-land. I've got CopperCam set up to export G-Code ISO standard, and the next option is to export G-Code Num version(I/J absolute). My laptop Mach3 that shows things right has IJ mode set to incremental, and I'll bet my machine PC has it set to absolute.
Problem hopefully solved, thank you, Russ!