Technically.. methanol has a specific gravity of .79. Water is 1.0. Meaning methanol is 21% lighter than water. The lighter the liquid, the less things like to float in it. The floats have a hard time staying afloat in methanol. Even tho they are at the very lowest possible point in the tank. So what happens is the liquid in the tank sloshes back and forth, this cuases the float to bounce. When the float bounces.. it cuases the LED to blink. If the tank is full all the way to the top of the neck.. the float wont bounce. As the tank level comes down, the float will bounce more.. and you can guage how much alcohol is left in the tank by the way the LED blinks.
If the car is sitting still and the light is "ON".. then it is time to fill it.I made a circuit about a year ago that was a delay.. meaning when the float was down for 5 seconds.. the LED would then light.. at that time, most prefered having the early warning of the blinks vs a too late we now dont have meth warning.
The GM gas guage on the Buick when it gets down under a 1/4 tank will bounce to E and back under cornering or stopping..etc. This is the same case.
HTH
Julio