bro there are two displays for mileage in that meter
one is instantaneous mileage which u get at that very moment, floor ur car and it will fall to 2 or 3 and then as the car becomes steady it will get normal again, press the clutch n lift ur foot of the throttle and it will be 99.9 like u said.
2nd one is Avg mileage which is the actual kmpl and u need to check that in order to know ur car's average and please dont be fooled by the instantaneous avg display and even if u did dont share it on forums as I have made u understand in a gentleman's way , others might ridicule u.
stay blessed.