Originally Posted by CoasterDan
I wasn't referring to the timing of the shift changes; rather, I was referring to the fact that the torque converter slippage allows the engine to rev higher and produce more power. Without a torque converter, the Powershift will sometimes feel like it's in the "wrong gear," requiring a downshift if you want to accelerate.
Understood. When the torque converter is not in lock up mode, the engine revs are free to change somewhat independently of vehicle speed, and the change from a higher to lower torque converter speed ratio provides a torque boost. A torque converter will always be more "responsive" to sudden engine power changes than a manual because of this effect.