Good Afternoon H969:
Your math is correct: FC + CC = TC. Given your numbers, FC is very low for your CYA level. I would also stop using dichlor/trichlor since both add CYA and yours is right on the edge of high. I would switch to bleach / liquid chlorine immediately. Otherwise, you are looking at a partial drain & refill to get CYA down. Also, do not add any more stabilizer (CYA). The target FC is 9 given a CYA of 80, per Chlorine CYA Chart.
pH is low. I would increase that ASAP to be within the range of 7.2 - 7.8. Increase pH by using Washing Soda, Soda Ash, or Borates. Note that Washing Soda is not the same as Baking Soda.
Use the Pool Calculator for dosing amounts for your pool. Input 28,000 as the amount of gallons along with your current readings. In the target section, input FC target of 9 and pH target of 7.5. Your other numbers look fine. FC and pH are the primary items that need to be adjusted, given your numbers. Adjusting your pH takes priority over TA right now. Regarding CYA, you are right on the edge. If you are planning a trip in the near future and you are forced to use pucks while you are gone and if no one will be there to manually dose with bleach / liquid chlorine, then I would do a partial drain & refill now to get CYA between 30 - 50.
Check the links in my signature and become familiar with the relationship between CYA and FC level. Forget forever the traditional wisdom of maintaining a FC level between 1 - 3 ppm. That's asking for an algae bloom.