Presumably the fuel tank was calibrated...

... in liters I mean it seems obvious when the tank is 11.9 gallons or 45 liters, that it was made with liters in mind, since it was mfr'd in Japan. Why I ask is that I'm starting to suspect that the fuel gauge ¼ tank increments are 9 liters each, right? Split the tank into 5 parts of 9 liters. Of course, as I think in gallons, I had been calculating that the ¼ tank increments were a little over 2 gallons, which made the math a bit hard, so I've adjusted to thinking about the gauge increments in liters. I wonder if our Canadian and Brit owners were laughing at us Americans all this time?

Based upon that notion, then:
Full = 45 liters
¾ = 36 liters left or 9 liters used
½ = 27 liters left or 18 liters used
¼ = 18 liters left or 27 liters used
E = 9 liters left or 36 liters used

And the point is when the gauge hits Empty, that you have 9 liters or 2.4 gallons left. What's puzzling is the fuel range light. I'm wondering how that is calibrated. Is it 11 liters or 12 liters? I'm guessing 12, but I'll have to pay closer attention in the future.

I know many of you laugh about this fuel tank obsession, but I like to fill up as little as possible. I'm used to filling up with 1 or 2 gallons left in my old BMW's 16 gal tank, so it rankles if I've got 3+ gallons in the tank and 150 miles in range, when I fill up.

I mean look at the newest BMW i3 range-extender. It only has a 1.9 gallon tank! That's to eliminate range anxiety of EV-only. Our CTs signal for a refuel, 3+ gallons, which is 50% more than a full i3!