Hello there,
If I'm not mistaken, there is a mistake on this page, specifically some numbers are reversed.

http://www.largeformatphotography.in...ws-factor.html

Near the top of that page UNDER Roy Harrington there is a table
Lens: Extension: Compensation:
He compensates the Aperture values the wrong way, closing them further when in fact they should be opened, correct?

Just thought I'd point that out, trying to be helpful

Best
Joe