Dear, I'm driving Altis 1.6 since May 2018.
Before 1st oil change, the mileage was pathetic: 8-9 local & 14 kmpl on long route.
5000 km onwards; started giving me 10-11 kmpl local & 15 kmpl long route.
10,000 km onwards; 10-12 kmpl local & 16+ kmpl on long route.
I recently (27 Oct) drove it from Abbottabad to Khanewal (4 passengers incl 3 children) & it gave me an amazing fuel average of 19.4 km per litre. BUT it was motorway from Abbottabad till Khanewal.
I zeroed the trip meter, filled the tank with normal petrol & then filled the tank again after 596 km. Total fuel consumed was 30.7 litres.
I'm using Taglon 5w50 fully synthetic oil, 34 psi tyre pressure, air filter cleaned, soft pedal & careful route selection even during local drives. Speed on motorway was between 90-100 km/hr.
I'm Alhamdulillah, satisfied & enjoying.