Is my tranny going bad?

[Crmsntide27]

Truck has 62,000 miles on it. Cruising around it shifts great. When I lay down on it a little bit it will delay the shift really bad. If I dont let off the gas when it delays, the truck will skip and buck really bad. Temps never get over 170. Have done two flushes since I owned the truck (brand new). Have contacted the guys that write my tunes and they sent me new files and it didn't help. No codes or other symptoms.