Yes, of course it's more complicated than that, but the way of the world is that they need a quick soundbite. My point was really that if they used a more reasonable figure in those statements people wouldn't get such false hopes. If you quote the highest number you've ever heard of for mileage on a car, then hardly anyone is going to get those results and nearly everyone will be disapointed. While some people are going to get twice the mileage of a standard version, most people arent, so quoting it that way is just asking for disappointment. I don't think I'm that far off here, the mileage database doesn't seem to show that you should expect double mileage from any of the vehicles with standard counterparts.