I think it would be more useful if the fuel/day UI showed range in lightyears instead. Move fuel/day to the tooltip. People can get very good at judging distance, but cross-comparing fuel by fuel/day is too inconvenient.
Similarly, showing days left of supply instead of supplies per day would be much more useful. That's a bit harder to calculate unfortunately. I thought I'd figured it out, but apparently I deleted what I had
What I kludged together below is mostly accurate from what I can recall.
T = total supplies
R = repair/recover cost
S = current supplies/day
M = maintenance supplies/day
If T - R > 0, days = (T - R) / M
If T - R <= 0, days = T / S