I may be totally off the mark here, so I'd like to hear how experienced users do this.
If I have parts being cut that need to be accurately sized, but are slightly off, I have been editing the bit diameter in my tool database & then recalculating the toolpath & then re-creating my part file.
Then I saw 'Proportions' in the FP fill-in sheet when loading a file & wondered if that could also work. Can I also adjust that to accurately make very small adjustments (ie: .01") to my toolpaths?