IIRC the US fuel economy test for cars is more accurate than the European equivalent, but that is beside the point. Electric cars have regenerative breaking and do better in the city than highway, basically they thrive in stop-go vs. ICE cars.
Also, somewhere on this site it is written: a good statement is to always assume 50% of what the manufacturer claims for range. Here, the tested range is 35km, so that is already lower than 40km and that is smaller frame&weight.
Just to show to never trust a manufacturer, there is a website for a gravity blade scooter:
They flash you a graphic with “35km range” and at the bottom of the page “well, actually, it is 12-18km in reality”, so they even contradict themselves on the same page, but based on the specs by Gotrax XR Elite/Ultra as comparison, the latter seems realistic.