for electronic calibration you need discharge E+ NMH completely untill cut off and next charge fully including final balancing stage.
This way PIC chip on DSP board will register new high and new low for battery and adjust SOC displaying accordingly.
You are the owner with biggest millage on 1000W Eplus I ever heard or read.
Did you noticed any mechanical issues with motor, like noises, cogging or loose torque arm, etc???
Any problems except batteries of course?