It is a good point, but I highly doubt the stated 40km range was measured with a rusty bike off road. I think it is fair of a seller to state their range in good conditions.

I’m missing something, what’s unrealistic about 15.5kmh? That’s absolutely crawling on a bike.

What he meant was to go 15.5km/h with a good bike on a velodrome might require 32.5W, but it would require quite a bit more power on rough dirt roads with a shittier bike