I have just completed a flight from Sydney to Brisbane using the default Qantas B737-800. Upon arrival at the gate, I noticed that my left and right fuel tanks were completely empty and the centre tank had 32.4% of fuel left. I had filled up 50.9% of fuel in each tank before leaving the gate in Sydney and I am curious as to why the B737-800 had consumed so much fuel . Could it be due to the long taxi from the domestic terminal to 34R in YSSY or the steep rate of climb to 35000ft ?
P.S. I seem to encounter similar problems with other default B737-800s but not the B747-400.