Guys: sorry I have to do this in liters and km :P
Techno - the numbers don't add up ??? I'm trying to figure this out for myself and I thank you for providing the input data [thumbsup]
(BTW tank is 14 liters of which SHOULD be 3 liters "reserve" as the light comes on)
Your bike uses 0.55 liters per 10 km if light comes on at 3 liters left, as it is supposed to. (11 liters on 200 km)
Then you should be able to go on for another 55 km after light comes on. If you only did 40 km on 3 liters reserve the bike used 0.75 liters for every 10 km - after going on to "reserve", and that can't be right.
Based on the total km on a full tank your bike uses 0.58 liters per 10 km. The 40 km you managed to go on "reserve" shows that the light came on at 2.3 liters left. At least that is what happened in your case.
I think we have to accept, and be prepared for, that the light comes on at different/wrong moments, maybe depending on riding style, uphill/downhill, curves, braking/accelerating a s o. Also the light might be based on an insensitive/inaccurate sensor.
I will check my own numbers soon and get back to you with my readings.
GUYS: again I'm very sorry, I'm triggered by numbers, but even I was bored by the end of my post :