For my 2008 D40 Dual Cab Auto;
Indicated 54,741km 6974.9 litres equates to 12.8L/100km
Using my phone GPS, speedo 118km = 110km/h GPS, so 0.9322 correction, so overall I'm getting 11.9km/l with nothing to ECU etc...
Not as good as "modern" dual cabs, but I'll take it.