All my piston leaning experience was simply putting the lever to auto lean, so excuse my ignorance. One method of leaning is leaning to the point of roughness (misfiring cylinder because it's too lean), so if you enrichen to the point of removing roughness would that particular cylinder not be running LOP? I notice reading FAA safety information they give the impression of giving their imprimatur to LOP, with the caveat of having proper instrumentation and calibrated yearly.