Here's a little trick that I've used to make seat allocations on NWA. No idea why it should work, but it seems to.

Go to NWA.COM and use view/change reservation for your reservation.
If it has your FB number in it probably won't have your status. Click on the number and change it to your old FD number. This picks up your old FD status (Pt in my case). Then do the same again and update with your new FB number - this time the status will be retained and you should be able to reserve the premium seats online.

Hope this helps