Am i being taken for a fuel?

MY D40 diesel auto Navara uses 14.5 litres for 100km which, despite the claims by Nissan that it is normal, I think is excessive. It weighs about 2900kg with tools, roof rack, bullbar and canopy, which I was told was the reason it uses so much more fuel. Nissan considers the latest test -- 100km drive in one hit that returned 12.5 litres/100km -- acceptable, but most of the tools were out and the ladders were off the roof. I have never got anywhere near that rate. A friend gets 9 litres/100km from his manual, the only difference, apart from the transmission, is that he has no canopy or rack and carries few tools, so his probably weighs about 2000kg.