How do I qualify for the 75C table in the ampacity chart?
UF can't beat the heat

Unfortunately for you, UF cable is like NM in that it can't be run at any higher temperatures than 60&deg;C:


  340.80 Ampacity. The ampacity of Type UF cable shall be that
  of 60°C (140°F) conductors in accordance with 310.15.


Now, if this were a tri-rated (USE-2/RHH/RHW-2) multiplex cable, or a direct burial MC cable, it would be something of a different story, but that's beyond the scope of this answer.