figures are 4.5 k/l
22L/100km
as i said this is over Cardwell Range & countless stoppages due to roadworks.
Maybe the biggest problem is the drag caused by the bed flys, haven't found a way to keep them DOWN during travel....... or maybe even the tug.
That figure is not nice, but in those conditions, is not surprising. It is moving the mass up and down hills and from standstill to cruise that is using the fuel, not the stone shield.
If you want to to investigate your fuel use further, do a full-to-full taken freeway economy run over at least 200km. You will more than likely (hopefully!!) see the figure drop to the mid teens.
Maybe fix the flappy bits first!