Mine is a Prosmatec, yes the mileage is much better than 8th Gen, mine does around 11-12 kmpl in summers with a light foot. A heavy foot gives around 9 kmpl (which was normal for 8th)
In the motorway I achieved 16.3 kmpl (AC on) with speed of 115-120 and not more than 120.
About the Econ, if you really concentrate to give yourself a headache only then you will feel the difference, car is slightly sluggish even though average is much better with Econ as compared to negligible lack of performance. If honestly you ask me, Performance on Econ is not noticeably different
Lost email account on which my i.d ali.archilounge was based