Altis 1.6 is not a very fuel-efficient car.
It can give you 9-10km/1L with A/C and an extremely lightfoot on the highway with zero to no traffic.
In local areas or short trips, it drops to 7-8 or even lower with A/C.
Altis 1.6 is paired with an old 4-speed auto, which is no match for Grande’s CVT-i, which proves to be more efficient than 4-speed auto tranny of Altis.
If Altis 1.6 was paired with a CVT, it would have been a very fuel-saving car in its segment.
Source: the owner of 2016 Altis 1.6.