[Perfectlap]

Very easy solution. Do an oil analysis after a few of those 3k mile changes and compare to a 10k mile analysis. I'm not sure if these labs can and do check for zddp levels but I would be interested in knowing the levels coming out of the car after a 3k change vs 10k. If there's a significant reduction below the recommended level (see T. Callas thread on the issue) then you'll know the answer for your engine.