I am mostly in the 40-50 band but on a good run please read this post: http://www.fordowner...ds-claimed-mpg/
I read your linked post, but I have to say that you should be very cautious when getting high mpg figures for certain stretches of road. I managed to get an average reading of 61 mpg after driving down a certain route a couple of days ago and had me thinking that I could have hit 65 if I had kept going! It is highly likely that these routes are averagely down hill, but that wouldn't necessarily have been apparent whilst driving. This high mpg would have been compounded if lucky enough to have a strong tail wind. Anyway my next journey saw my average mpg return to it's long term average of around 51 mpg which I think is a more realistic figure.