After my last service (20000 KM), the mechanic forgot to reset the "next service" from the i-Drive, so whenever I startup my car, the next-service
information is never correct.

I just did the service for 40000KM on last month, the mechanic did reset the next-service, but now it shows 35000KM. Which means I don't need any service
within the next 35000KM? I wonder if this is correct though.

So, check the i-Drive; if there is no such an information, ask the mechanic; if it shows something strange, ask the mechanic.