OK I don't think that answer really gets to where we need to go so maybe I should drop back even further to the issue of:
What is a "mental examination of a confirmed concept" if one were to accept that version of the doctrine?
In asking about a "non-aggression principle" maybe that is too complex an example. If the suggested translation were to be accepted as accurate, what would be an example of a "mental examination of a confirmed concept" that would then be considered a canonical standard of truth?
Again, I am not convinced this translation is a good one, but in order to examine it let's presume that it is and look for an example of how to apply it on its own terms. Can this construction be applied consistently with what we know about the rest of Epicurean philosophy?