Audiobooks discussion

After many years, I finally have started listening to some books on faster speed. But I was confused because it is different on different devices. On my iPod nano, the only options are 1.0, 2.0, and 0.5. The speed of 2.0 is fine for me on many books. But on my phone on the Audible app, there are gradations - 1.0, 1.1, 1.2, etc. I can only listen to about 1.3, maybe 1.5, certainly not 2.0. I looked around on line and found that somebody actually timed it (I was thinking of that but was too lazy) and found the 2.0 on the iPod is really more like 1.25. That's all fine, I just thought it was weird that there is a discrepancy like that.