I just dont think people are calculating their fuel usage properly..
they assume that E on the gauge means its empty..
If i went by my fuel gauge id be filling up every 250-300 kms
but i get closer to 450 from a tank of pure suburb driving
remember..
fill fuel tank to the top
reset trip
drive drive drive
fill fuel to top again..
Divide the litres of fuel you put in by your trip meter.. eg
42l/ 298kms = 0.140939
in other words.. 14.09l/per 100kms