Only uncirculated notes are worth sending to TPG because many people who collect uncirculated notes will pay more if the note is 65 versus 62 or 63. It does not matter if a 65 is not really a Gem, all that matters is the number on the holder. The same thing has happened with coins, and the prices paid for "finest grade" coins are staggering.
Circulated notes are not worth getting graded because everyone automatically assumes they are overgraded no matter which company grades them, so they always sell for discounts versus catalogue.