I use a advanced warp drive with an 1/2 ratio which does mean that the consumption is 2 Pent per LY. The correct display in my suggestion should be 495AU/ 247 (248)LY. Is that a bug?
Thanks for your report!
Eleon created this Pentaxid UI without the Dialogue modifications in mind - that you could increase the warp range.
So for now a bug, they won’t bother for some time (cause Vanilla doesn’t use such fancy stuff)