Not sure which engines you are involved in, but the one I used to operate was the Allison 501-D13 on the Lockheed L188 Electra.
The Limits were TIT 971 C for take off and max torque of 4000 Horse Power, (gearbox limit).
we used to set 971 for TO. (or 932 for reduced power TO.)
The only time we were Torque limited was if the temp was below Zero, and then we hit the 4000 HP limit with less than 971 TIT.
At altitude, say FL 220, you would never reach anything like the Torque limit, in fact I seem to recall that in cruise the set TIT of 847 would give about 1500 HP so if you pushed the power lever forward to 971 I doubt you would get 2500HP. The air is too thin for the engine to develop that much power.
This is for an engine with a single shaft and constant speed prop. I don't know if the same would apply for a free turbine engine like the PW 125 or PT-6 engines.