Like Smitty said, it's about thier over agressive marketing. When you get a chance, do an internet search for something about "synthetic oil, or motorcycle oil". Out of all the results, try finding one that is not sponsored by Amsoil in some way. They have some very good articles, but I doubt that it's not biased in thier favor. On the upside, MOBIL1 vtwin comes out very good on all of thier tests. If Amsoil says Mobil1 is very good, that's what I want to use.