I noticed that after topping up fuel the gauge dial seems okay/normal, but the RANGE indicator takes some time to rise to a corresponding fuel level, according to my expectation.
Also, when the engine starts from cold position the range indicator shows "fast" fuel consumption. While engine idles (between High revs to Normal revs) before I even drive out of driveway, the range drops by about 2km's. Could this be the fuel float or some other problems?

 

The speedometer shows you the current speed and the fuel gauge shows you the current fuel level. Simple data. The range indicator is entirely different. It makes a calculation of current fuel level and current fuel consumption rate and average speed. If it integrates these rates over 10 seconds when you are at idle in the driveway it gives you a vastly different number than if you are doing 70 MPH on a freeway. If it integrates the same data over seconds or a few minutes or 30 minutes under the exact same conditions the calculations give very different results. I wouldn't worry about it at all, some engineers in a lab decided on a set of calculations not at all related to your car in your situation.

 

If it's always behaved this way, I wouldn't think it's a problem. If it suddenly and drastically changed its behaviour from what it was doing a week ago, it might be worth looking into.

 

Hi, the fuel range indicator at idling stage is not usual. I will have it checked electronically.