The only way that you will know that the gauge is accurate is to run the tanks dry. Either the gauge is correct and the engine will stop at fuel 0 wich is ideal or not. Who however is going to try?
The point is, Yes it will produce figures that you are used to and they seem correct. You expect 2000 kgs remaining and voila it says 2000 kgs . If it is really 2000 kgs of usable fuel is questionable.