On a trip such as this I get sub 9. (without trailer)
BNE to port Macquarie 2 weeks ago, 8.3 down with tailwind, 8.7 back. Retune definately improved highway fuel consumption :D, but made city consumption worse...:(
I except what you are saying. However if you can't buy a good example car from a main dealer, with a month to prepare it beforehand. Then there is no need for this site. As I may as well buy a landcruiser !
If a car can't do, withen reasonable limits & with adequate preparation. What it designed to do. Then it's nothing.