I recall reading an Amsoil rep saying if you run enough tests you get the results you are looking for. I'm sure Amsoil ran tests to get results they were looking for with their filters, as well as their oil, as other co's do.
I think they make some good products, but slowly I'm losing respect for them. Too many reps pushing product is not good IMO for any company.
Just forwarded from a friend some data re: Pure One filters: