Perhaps more without the power than with?
Dave: when I had a new Giant Trance E+., a 25 km/h e-MTB with 500 Wh battery and I used to ride it on the flat (forest service roads at hardest), my maximum range in standard Giant Eco mode was 40 miles, and it was typically less than that... There is something I won't understand here. Note: On the flat, rider's weight only affects the power consumption for acceleration and for nothing else!
P.S. SL e-bikes use 2-3 times less energy because they rely very much on the rider's input.