I checked the accuracy of measurement compared to the counter of the water supply company. The result is astounding! For 1 liter of water charged (flow was almost laminar), the first counter measures 0.5 liters and the second 0.7 liters !!! Given this result, it was useless to check the flow measurement. I will complain to the manufacturer. It is unacceptable to let out a factory complete rubbish meter.