Just as an FYI:
TPA (The Perfumer's Apprentice) is the company name. Within the company; they offer a line of concentrates that are specifically made as flavor concentrates... and these are the
TFA (The Flavor Apprentice) line, and the ones we use for vaping DIY. (They also make concentrates for making perfume, and these are NOT appropriate for vaping. I don't know anything about their new(er) "The Flavored Herb" line.)
As long as you are buying from a established, reputable, reseller dedicated wholly to vaping; you should be just fine (in that the products are appropriate for vaping).
For whatever reasons, resellers (as well as review sites) will use either/or for their abbreviation.
To make matters even more confusing; some resellers (those who offer their own "house" brands) will re-bottle/re-label TPA/TFA products (along with other name-brands), with their own branding. Personally, to avoid this confusion, I try to only buy manufacturer branded concentrates. That way, I have a fair certainty, that I am not unintentionally duplicating concentrates I already possess.