Not sure what you read, but the only way you don't have ASF with armor that lists as HAVING ASF is you take the enhancement in ES tree to eliminate it. Otherwise you need an augment to remove it (up to 15%). All proficiency guarantees is action penalty removal.
BTW.. the SLA blasts are also vulnerable to ASF.. no matter what anyone here says. If you want to be free of it, take the enhancement to remove it.