Dear chanaka
My wife too have a Daihatsu Mira (2017 new model), but fuel consumption doesn't even close to yours
Realistically in Colombo traffic, mira does 13-15Km/L, this car is our daily commuter..
Outstation, it does about 20 - 25 Km/L depending on how fast & hard you drive.
Actually my Axio Hybrid does 14-16 Km/L in the same route.
Mira being a fully petrol kei car, with no hybrid battery what so ever, i believe, this is a versatile city car to use as a 2nd vehicle for longer period.