My FC is always 11+km/L in SG, (80/20 city/highway ).
Last week cruised on malaysia eastcoast @most economy speed 90km/h, to my surprise, full tank can clock 730km, 19km/L!
In NS highway @120km/h, engine efficiency drops, FC also drops to 15km/L
what a huge difference! driving style is really important factor for the FC.