When selecting a carrier and a star, the warp speed ETA is the same as the base speed ETA. Star to star is fine, but in theory, if I created a warp gate on Alakurops, the ships would speed up, as they are travelling from a star with a warp gate.
This is a known issue as far as I remember. You have to wait a tick for the eta’s to be correct shortly after new gate is built/destroyed. I recommend any time you are doing warp gate math, just think of each 1 tic “warped” equals 3 tics “normal”.