I achieve 21-22KMPL on regular usage. ARAI certified 25.4KMPL. So the gap is 10%.

My regular usage is Chennai to Cuddalore on Friday evening (Fetching 18-19KMPL) and Cuddalore to Chennai on Monday morning(Fetching 25-26KMPL). Weekdays usage would be hardly 15km (Fetching 13-15KMPL).

I never reset the average mileage in the MID. It shows 22.5KMPL over the 23000km's. And my Excel work also confirms the same.