Just did Sydney to Brisbane and for red light on and a little in the sub left did just over 1100km so about 11.2L/100km. Not towing but was loaded with about 100kgs, steel bar and winch. Only 3000 on the clock so happy with that. Speeds varied from 80 to 110. On the way down averaged about 13L/100km. Dunno why.
Jas