yes no shit, i fill full tank, press the trip-meter, drove from sydney all day way to Kemsey (450kms), the arrow shows just touching half tank on the higher side, i think may be i'll fill up to full again, and it gets full at 22 liter.
so... around 4.8-4.9L for 100km. and the car was fully loaded.

looks like next time im driving up to Brisbane without filling up >_<