I have just returned from a trip in my 2005 Toyota Prado, and was unpleasantly surprised when I calculated my fuel consumption at just under 15 L/100 km. I was pulling a camper trailer, mostly on freeways with very little stop/start driving and I would have expected much better fuel economy. I got better from my old V8 Falcon. Would this be in the range you would expect?
Without knowing more about the roads you were on, the speeds you were traveling at and the load you were hauling it's hard to say what you would get. But the Prado is a big lump of a thing, pushing a lot of air, and I bet it was working hard. It's probably within the ballpark in the conditions.