I believe that the desired response was KK, indeed, as the actual confirmation did not happen until the mileage cert was surrendered at checkin... Of course, I may just have it all wrong.
...OK, that's the way it used to be before the option of doing it online on .bomb... now with that option, I suppose we can just find the Os and Is, book our flights an apply for the UG. Can't say that I've tried it myself...
On that subject, have the Y->C upgrades from M and H gone away?