This is my thought as well. I also think the 1500 RPM launch helps by not loading the rear suspension at the start line, thus keeping the car on the rear tire longer through the launch.
I noticed that on a couple of the launches where I let it load up on the suspension 2500+ rpm launch, every run I had to pedal. I'll have to add it to the list, Try runs off idle and loaded suspension just to see the difference.
