I'll throw this out there, aren't different additive packages more adept at maintaining TBN longer, thus it don't read as high to begin with? Meaning the amounts in there don't deplete as fast (what's in there is "more durable" for lack of a better term) as other additive packages?Kind of a low TBN for their “advanced“ oil, no? Isn’t that the 15,000 mile oil by them?