Sharing my experience....
Got new honda city 2019....
For first 1000 kms....
It gives me around 11 to 12 km/l on long route and 8 to 9 km/l within city
On 1000 hrs inspection, i complaint the same to honda guys, who once connected the computer found that factory running of engine is not clear.... the led infront of said parameter was red. So they keep the engine on with computer attached and after 20 mins the led goes green on their computer. They give thumbs up that now it will give good average.
Then i further travelled around 200 -300 kms... with rpm less than 3 and overall speed around 90 the avrrage improved to 14.5 per liter.
Today i travelled again 300 kms.... first 150 km with speed of 110-120 and on return next 150 kms around 80-90 on motorway.... the average of complete trip is 16 km per liter.... AC remained On throughout the journey at speed 2.
My car has done overall mileage of around 1600 kms...... i think its improving day by day with improvement in my driving technique.
Since i am unable to drive on short route within city.... so i cant comment...
I hope it helps ...... was also really worried about mileage issue initially...... now a bit satisfied with mileage....