As trucks are governed to a Vmax of 90 kph, and some even to 85 kph, I would suggest you get your speedometer checked, because it sounds like the advancement, required by law, is too high. It shouldn’t show more than 7% more than your actual speed. Truck speedos are more rigorously controlled and show an average of 2 kph too much at 80 kph, so trucks overtaking at 101 kph is not normally possible - of course, speedo manipulation does occur, but it isn’t so rampant that they all overtake at 101 kph.