Help-Fuel economy of fabia

I people ..this is Mk from chennai ,i bought a fabia 1.2 ambinete petrol  last week,As part of a dealer discount package i got a full tank of fuel free of cost..The car  has now run 319 (AC ON )kilometers and the fuel level indicator has come one notch below reserve mark which has 6 liters of fuel.

assuming that  in the that 45 litre tank . consumed petrol is 40 liters it has has hardly given me 7.9 KMs/litre.But its hardly a 1,2 engine and the delaer prmised me a mileage of 12 in the city and 14 in the high ways.please advice

(PS-i am not very hard on the clutch)