Well there is one way - the ESC is autocalibrating the top end so let it do that. Use a P-mix to mix throttle into throttle some negative percentage - say 25%. Plug in your pack, run up the throttle to full briefly then shut down. Now flip the switch bringing in the negative mix and the next run up to full throttle should be less than full throttle. You'd need to do that each time you fly and remember to start with the switch in the correct position.