I know this might be crazy, but hear me out...if the RIDER outputs more watts, the range is extended.
ride harder, go farther
Only kidding, kinda. Seriously, higher effort from the rider and a higher cadence nets a much easier load on the motor and increased range.
I'll also add that rolling resistance, rotational mass, and aerodynamics play a HUGE role in range. Same thing in road racing.
Lighter wheels, lighter tires, tubeless, and aero bars drastically effect the range. It's the same if I ride my road bike at 250 watts, if I'm on my race bike, Pinarello Dogma with Campagnolo Bora Ultra carbon wheels on Vittoria Corsa race tires, it's crazy easy to sustain a higher speed or go farther. If I'm riding my winter bike which weighs over 10lbs more and has much heavier wheels and tires I can't go near as far or as fast at the same effort.
Factor in weather/terrain and we're all wasting our breaths. Which is usually how range conversations go.