Hilltopcruiser

Thackeray, I used to think this and had the same theory as you, however, the discrepancy was caused by the fuel pumps at the station. They are all in accurate and will stop pumping fuel into your car all at different times depending on what the sensor is set to on the pump by the supplier. Infact when the pump goes click and won't allow you to add any more in, there is usually still between 3-5 litres of volume left unused. I now fill mine to the actual maximum and I no longer have a discrepancy. I don't have fuel splash back cover fitted in my nozzle hole which makes this easier. I no longer have a fuel consumption discrepancy or its so small and inconsistent I can't call it conclusive. I am also assuming you are taking the 10 litres of reserve that are kept in the tank when the dash shows empty?