Normally,(General Helicopters) the Torque stays more or less with the physical position of the collective, while with more altitude, the MGT will rise. The only thing could be, that the Apache has a limiter, but i doubt it. The Torquebehaviour is strange anyway on the DCS AH64 (way to jumpy) If you pull a bit of G's while flying with, lets say 90%, you have immediatly 120% A few % would be normal, but not 30%