Autofocus adjustment on K20D

I was frustrated with my Fa 31mm for backfocussing issues. adjusted the auto focus to -10 after all testing and was still getting backfocus from F1.9-4; I considered Eric Hendrickson and the pentaximaging.....too much hassle for autofocus and I began to wonder if it would be better to get a K5 body and forget the K20D,,,,,,then was able to use debug mode published by these guys
http://www.andymcm.com/blog/2010/01/debug-mode-on-pentax-k20d-dslr.html

Needless to say I did a global adjustment to +30 and walaa....It is pin sharp. Wow. I had tried +20, +40,+50 before settling on +30 and it is spot on.

Anybody else with similar issues on a high end lens like to Fa 31mm. It was a lesson for me in that most lenses are well built and just need better calibration for exceptional focussing on any particular body