Top speed is not reached

Hello, just have a longer highway tour behind me and it has to be noted that the top speed of 228 km/h is not reached by far on a level track. Clubman Cooper SD, Sportautomatik, EZ 2017, 190 hp. According to appearance 228 are registered. Reaching I do on level track and long run but only a maximum of 222. If you take the tacho deviation into account the car does not drive even 220… Does anyone have experience with it? What is your Clubman SD running?