G64 P and Q

The Backplot error I was seeing was weirder than that. I could watch the tool follow the programmed white line pretty closely (with corresponding numbers on the DRO) but as the tool continued on down the next line, the red line that was "supposed to be" the "true tool path" actually moved from the correct position to nearly 0.5" away from where it should have been, following the tool as it moved down the next line. And this was regardless of what the Q setting was in the G64 command.