And that doesn't matter. It lists ground speed, true air speed, indicated air speed. All that is shown. Does it matter what the alt is, when alt isn't used in any of the computations?
Speed, wind, fuel consumption, fuel remaining, is pretty much all you need. It takes that and gives you "this much time left" and it does a very simple "this much time vs this much speed = this much range" based on what it already has.