New board computer with current consumption display

Hello Mondeo driver, I have a Mondeo Ghia SCi Kombi Bj 11/2003. Since I have the car, I have had difficulty with the consumption indicator (always about 1 – 1.5 l/100 km to less than calculated by refuelling). The following ads were available: average consumption, average speed, temperature and still to be driven kilometers. My workshop was very busy and has changed several times tanker, board and software. Unfortunately this did not bring any improvement. After I now m In addition to the above data, I also have another display, namely the current consumption. You can see very well how it changes in case of gas gain or decrease. In the sliding drive (if you approach a traffic light without gas), the display falls to 0.0 l/100km. If you take out the gear then there are only two strokes left. If someone has already experience with the new computer and from where you can contact a customer service engineer, a new computer has been installed. Does the board computer have the impulses? Unfortunately, my friend couldn’t give me any information. Maybe one of you knows something about it. Would I be happy to hear from someone.