I have a 2017 Nissan X-Trail. When I set the overspeed to plus-2 it does not give a warning until the speedo shows 10 km/h over the limit, which rather defeats the purpose. What is the point of having an overspeed if it is that inaccurate?
You would like to think it is accurate. Check the speed using a GPS, and then adjust the overspeed setting to compensate for whatever error it shows.