Remember an oil may work well in one type of engine but in another oil turn to tar, Amsoil will show results on how good their oil is , but ia another engine may not do so well I don't think the results would be printed in their advertising. The test is very narrow in as much as the vehicles and their operation. With cold starts short engine run time etc. the results may be different,looking at the uoa's we notice different results on the oils the constant would be similar operation.