Hi Dude
OK. Fwiiw, I think the DRO for Radius Compensation is wrongly labeled. There was a problem with it way back when, and it was supposed to have been fixed, but in a nutshell I am strongly of the opinion that the number which should be entered there is Diameter, not Radius.
I have done a lot of testing of the display, and entering the radius simply does not work. The display is all wrong with radius.
So it may well be that the calculations for surface speed also assume the number is diameter. That would account for the 2:1 ratio. Try it maybe?
Cheers
Roger