Sorry, this is not a straightforward answer to your question but I had three operational upgrades with NW in the past three years or so. The last one was in May on TPE-NRT. I was booked in V (very discounted fare) and it was the final day of a string of early May holidays in Japan. Thus, many travelers going back home and the NW9 was oversold in the economy.

I am a Platinum elite and when I checked in -- it was about 2 hours before the departure -- the agent told me that I may well be upgraded at the gate. But as she processed my boarding, she said, ''Oh, you are already upgraded.'' So I got a business class boarding pass at the check-in counter.

On another occasion in April, I checked in and got my economy class boarding pass. It was NRT-SIN.

I went into Akane, one of the three NW lounges, and hooked to the Internet and checked on the NW site my reservation for the flight I was going to take. I typed in my PNR reference number and it showed that I am in the business class for the flight. Well, I just guessed it was operational upgrade and so it was. My boarding pass didn't go through at the gate and the agent rechecked it and gave me a new boarding pass for a business class seat.

I find that their travel itinery function quite interesting -- real-time.