Lehner Power Ratings Help

[What's_nitro?]

So what's up with Lehner rating their motors at the same power at the same amperage for all of the winds in a series? Like this:

1940/6 - 1400W @ 50A
1940/7 - 1400W @ 50A
1940/8 - 1400W @ 50A

And so on down the line. It would seem like this contradicts the properties of electricity. You need more voltage to put the same amperage through a higher impedance. And thus with a constant amperage there would be an increase in power output as the impedance increased. I want to upgrade my Rustler to a 1940, but, I really don't want to have to cram an 8s LiPo in there too! Not to mention a controller that can handle the voltage. Help?