My '06's milage is getting over the board. The relationship between the display and the, "guess gauge" is increasingly random.

So, to protect myself, when that thingee starts blinking, I'm looking for a gas station. If it's in the evening I'll park it until the morning, otherwise any station will do.

In short, you're too rational. Look at the whole thing (display, gas gauge, fill-up) look at as magic.