Originally Posted by aleph08

I've had an NH ground agent tell me at NRT she has seen such mileage number for the first time two weeks ago, even though it's been valid for more than two months now. So I wouldn't be surprised if it was not recognized at various airports around the world.

I still have a problem with different carriers (LH, TG) putting the new number when booking online, so I've had to call the reservation centers to have it added manually. So I suppose it might still take some time before all the systems will be integrated.