Hi there, I have almost the same vehicle (remapped 150HP 10v 2002). I have a little difficulty to interpret your message but I am sure your English is better than any attempt by me at your native language
The computer will give 3 readouts for fuel consumption (mine is in miles per gallon (mpg) not l/100km).
1) it will give the average consumption since the ECU was last reset (battery disconnected)
2) it will give your instant mpg, as you are driving.
3) on more pushes of the button it will give your average mpg for the journey (journey B) you are making at that time.
If you set the computer readout on 2) you will see the mpg go up and down depending on what you are doing with your right foot. If you travel at 100km/h and lift your right foot off for a long time the readout will go to a maximum and on my car this is about 144.3 (I think) mpg. It never goes above this even though there is no injection of fuel taking place.
Floor the pedal with the right foot and the readout will go down to less than 30mpg. (I will leave you to convert these amounts to l/100km
My overall average mpg is more than 52 - but I am gentle with my right foot ....... mostly
Hope this helps, Jerry