Attached photo is a crop from the best, of perhaps forty, attempts to adjust focus on this lens. K-5 is set at maximum correction here. Any less correction, or correction the other way, moves the focus further forward. Camera was tripod mounted, 45 degree angle to chart, center focus point, flash used, shake reduction off.
I successfully corrected/confirmed a Sigma 18-50 F2.8, Tamron 28-70 and 70-300mm kit lenses, 100mm F2.8 Macro, and Pentax 18-55mm kit lens, plus verified that several fast manual lenses were focused almost exactly where the focus system suggested, far better than this, and mostly slightly back focused.
Also, I took another 60 or so photos of flowers, brick walls, and random objects using this lens with both the K-5 (before and during adjustment) and K10d and not one was in good focus and most were completely unusable. However, photos that had something in the frame (somewhere) that extended ahead of the subject always showed better focus in front of the subject. To confirm that it wasn't the camera I tried the other long lenses and I achieved sharp to acceptable focus on all the shots with the Tamron 70-300mm wide open at 200-300mm and most shots with the 100mm macro wide open, all hand held.
There was certainly room for error on my part, both in photographing and making corrections with such a long and fast lens, but I should've got at least one sharp shot just by chance. Either that or I need to sell my gear and start making mud pies for a hobby - soft is good there.