By the way, I have reported that I feel that I read faster on the KA1 than on the KPW1.
It seems to be 'officially' confirmed by both readers. I've been reading the same book on both of them. I read on the KPW1 in public transport, and on the KA1 at home (if I have time to read), until I get a cover for the KA1. Thus, I'm leapfrogging chapters, from one reader to the other.
When I now set them to the same chapter, these are the results:
At this point, the KPW1 says Time to Read, 6 hours, 12 minutes. (6.25 hours).
The Kobo Aura ONE says Time to Read, 5.2 hours.
I know the Kindle is spot on, as long as it isn't hit with the "From now on, I'll show you HALF the time you ACTUALLY need"-bug. Assuming that the KA1 is correct as well, that would mean that I'm reading 17% faster on the KA1.