eHowl, to answer your question as to why you cannot move it to other apertures. As a matter of fact, you can, with older Nikon film cameras that only have a shutter setting on the camera, aperture size is controlled on the lens.
But with the newer analog SLRs etc, the aperture setting can be controlled from the camera body itself, so the lens has to be prefixed at 22 so that the camera can 'electronically' change the aperture based on the settings you input for aperture on your camera.
Not too sure about the serious techincal aspects. Hope this helps.