Chris, it is quite hard to be sure from that vid, due to the short distances being travelled, but looks to me that the X travel is constant. Surely if you were in CSS and G95 then when the spindle speed increased the axis feed should also increase to keep the feed per rev constant?
If you have time and are willing to test it would be nice to know.
Can you run some code cutting air in CSS as a test, what would be good is if you run from largest Dia you can turn into almost the centre and observe if the axis feed per rev stays constant as the spindle speed increases, ie the axis actually travels faster because the spindle is going faster. Also would be good if you can time that operation. Next reverse the operation, ie start from centre and work your way to largest dia and see if it behaves correctly and also see if there is a difference in the time it takes.
I will try when I get to the workshop later on, unfortunately I am stuck at home doing my tax but it gives me a good excuse to go down to the workshop later and forget about tax for a while
Hood