Maybe your right Cleanclear however at 55 I'm no racer. Short journeys fully laden, engine not getting warm for the first 3 or 4 moves, must affect the consumption. Ford motor company have always been poor with mpg IMO. Many 3 point turns so I don't reverse off drives, may not help the tyres..
I like my van but when I change it, it will be to the next size up. Just sayin.