The focusing screen must be removed completely and then re-installed to effect calibration. In any case a collimeter is a more accurate test/calibration device than any lens.
Under normal use a Pentax 67 should not require focusing screen calibration, unless the meter coupling chain has been replaced, which necessitates removal of the lens flange and shims and replacement; this process effects focus accuracy, albeit only very slightly when done competently, but enough for accuracy of focus to be an issue under critical inspection. If calibration of the focusing screen cannot be achieved after removing and reinstalling the screen and fascia, it may indicate that something has been done involving the lens flange (e.g., what I said above, service of the meter coupling chain in the event of breakage). Even something as seemingly benign as a shim/spacer substituted or missing will have an effect on focusing. It can be difficult to prove if any work has been done on the front involving the coupling chain/lens flange/mount etc. But any miniscule tell-tale signs of adhesive on leatherette patches, or misalignment of same, may point to interference.