Our 2001 Prosmatec gives us around 8.5 km/L with AC on is Islamabad's traffic. Last time we used Hi-Octane from PSO and it gave around 9.5 km/L.
Hot and humid weather increases the consumption. So your figures may be correct. Although they do seem somewhat high.
Did you buy the car used? Maybe someone sold you a car with a lot of mileage with the odometer backed up????