with my 2003 jazz I have been able to hit the fuel consumption at around 3.5l/100km ( lowest I ever got) when I was driving like him on straight road at 80km/h with good summer tyres at 0 incline just to see what's the least I could get.
But seems like this guy has been able to 2.2-2.3l per 100km consumption with his 2009+ jazz? wtf? 
Is this possible with the 2009+ jazz if you really try and drive like a granny at 80km/h?
while doing 17miles of downhill, tailwind and 50mph motorway driving, yes it is entirely possible to see that figure for few minutes.
I have seen 72mpg for a good 10minutes on my way to Oxford.. but by the time i reached my destination over 60 miles away the average came to about 62mpg and end of the day with 200miles travelled I was showing 55mpg so the longer the trip the lower the figure mainly because you have cycled through all possible scenarios and not just the most ideal one.
On a downhill section of a motorway at 60mph of something reset your trip meter and see mpg climb sky high.
