A few possibilities:
- He simply misspoke
- $141 used to be used for backlash but has changed. This seems unlikely but it’s possible. $161 is Y-axis backlash compensation.
- He goofed and misremembered
I don’t see why a chuck rotary would have any more backlash than other systems. In fact, I’d expect it be less than a belted system.
Note that the value he enters (600) would be appropriate as a current value in milliamps but wouldn’t be appropriate as a backlash correction in millimeters.