[nativepaul]

I would have thought that torque limiting is a different name and implementation for amp limiting that has been around for ages, with torque limiting holding the amp draw at a maximum level plateau, rather than shutting down when the maximum amp draw is hit.
Motors have a reasonably static KT (torque per amp) so when you drop from 3s to 2s with the same gearing your amp draw lowers and you wont be getting near the torque limit you set for 3s, gear back up to the same speed and the amps will try to increase and you will be riding the limit harder than you were on 3s.