I'm not a scientist and I don't play one on the net..I'm sure Amsoil is good/great stuff, I know many fleets in TX used it, personally, I think it's too much $$ so I'm cheap yet still think M1 is overpriced but, I use it to get 5K OCI's on low mileage cars (1x annually O/Filter change), 7.5K on driver's...their reps are at all the cars shows w/ lots of pamphlets/hype/ proof, etc. but really, when is the last time you really knew a motor failed because of the BRAND of oil??
maybe the change interval/the level ran very low/the oil was contaminated or SA "clearance oil" and the owner didn't know, etc., but cm'on..aren't we all here enjoying the "semantics"
anyway that's my "vent" for 6/9...Jeff