Completely agree; a PC is a much better method to judge filtration efficiency than is a UOA. But as you noted, and I've said countless times, once a minimum efficiency is met to satisfy the engine, anything "more" (better, etc) really does not manifest into tangible results in true wear data. There are three contributors to the wear issue, and wear is what we should be most concerned about. 1) add pack 2) filtration 3) OCI duration Those work in concert to establish low wear. But they are not linear in their response, and they are not mutually exclusive. From everything I've seen, the wear is most greatly affected by the barrier layers from the oxidation of oil. Run it longer, the wear goes to near-zero. It's the whole topic of inputs versus outputs. Hence, my constant harping on the ROI (be it lubes or filters). At some point, good enough is good enough, and more ain't necessarily better, unless you greatly shift the operational terms (supe- duper cold, silly-long OCIs, etc). This is, of course, predicated on a clean running engine that has no neglect in its history.