How are you measuring energy consumed? Via a voltage meter or the % readout on the scooter?
Power consumed by the motor is related to torque output, so for a given distance under the same conditions you wouldn’t expect to see difference in energy consumed .e.g Wh/km.
I suspect what you’re seeing is related to how you’re measuring energy consumed / Wh. If you can post your raw data that would be helpful.
The best way to go about this is to measure battery voltage directly so you don’t have another layer of uncertainty from how the display interprets the battery capacity.
Even doing this, you’ll still have to deal with voltage sag.
Voltage sag, which has a variety of causes (chemistry, internal resistance, temperature), causes the battery voltage to behave non-linearly as you load/discharge it.
It makes estimate battery capacity with voltage unreliable.
If you run the scooter in shortish segments (1 to a few km at a time), give the battery some time to return to nominal temperature/state, then make your voltage measurement, I think you’ll have much better (more linear) results and should see consistent Wh/km, all else being constant.
What is the purpose of your project?