Your link is from Gerald Newton's site. Did you know that he started his form up again after a bout with being SPAMed?
Mater of fact the very latest post of his was about conduit bending. I'm not a conduit guru that has the experience to answer his question but maybe one of you guys can.
The subject is:
"Opinion about the Benfield Conduit Bending Manual by Jack Benfield - Gerald Newton 23/PST Tuesday/January/24/06 (0)"
It's another good place to hang out. http://electrician2.com/elwwwboard/wwwboard.html