Ok, amsoil would not sell to major chain stores because they did not want to put the small shops/ distributors out of business. They had a deal worked up with autozone a couple of years ago for 45 million dollars on the first purchase, but they would sell it in the stores for less than what a small shop could get it for. Now the API certs., they did it on thier bottom line products but not thier top of the line, why? It costs 300,000$ for one wieght from one base line oil, let's say they had to buy the base oil from somewhere else they would immeadiately have to fork out another 300K to have it certified. They did check it the first go round in the 80's and it passed with flying colors and they felt they don't have the need to do it again.