@KamranAslam
May be LOS (Line of sight) although it moves little but due to LOS, one could not understand the change.
In my Corolla, even physically petrol is up to the cap and physically no space left but even then it is still a very very minor lag under the "F".
Might be that "minor lag under F" is something what you are referring to "tilt view angle" or difference in LOS.