31% ?!!! Wow, that's a huge difference. Even 5% is pretty large. Since most decent motors are around the 85% range, 31% less would put it much closer to that of a nitro motor.
Seriously, if a motor is pulling ~250w average with 1500w bursts (typical average), then that low of an efficiency would result in really high motor temps. I'd like to see how they got those numbers...