I have 1.8 Altis 2009 shape, Model 2011. Its gives me around 9.8 km/l without AC in city and with AC it goes to around 9.2 km/L . Keeping in mind i dont drive with with a lite foot. If i'm careful, you can easily go to 10.4 km/l with AC.
On Motorway it gives me around 12.5 km/L with AC. You've got the added feature of Airbag + altis feels better as obviously its top of the line. Plus when you are in mood to have alil fun, 1.8 is the name of the game
*Mine is Manual Transmission