As others will no doubt suggest, perhaps you could ask your Pentax service centre to 'tune up' your K7 and the two lenses that are having problems as a package.
That's the only way you will solve the issue once and for all, due to the issues with lens and body tolerance variation that this article discusses:
LensRentals.com - "This lens is soft" and other myths
The same issue crops up with all autofocus systems and cameras quite often. I notice from lurking around the dpreview nikon forums the same thing crops up frequently, and it seems Nikon do tune up body and lens as a package under warranty if the customer has FF/BF issues. Maybe Pentax will do so too.
'Softness' as an issue is harder to talk about because it needs to be defined better. Some example soft JPGs would be useful to see in order to understand your issue better. It could be caused by many many things - poor focus, poor lens optics, camera movement, motion blur, JPG settings, etc etc.