BMW does not go by mileage service.
Its condition based. IE how many miles you drive and how hard you drive the car or by time.
On your 3rd oil service(right around 30K usually) it prompts to replace the engine air filter, diff fluid and spark plugs at 30K miles, I also believe manual trans fluid.
BMW Master Tech/Diesel & M Specialist '15 X1 35i(daily) '02 530i (PT6262 turbo/E85fuel) 510whp @ 17psi