CDF:

I had a similar problem on a PVD-LAX flight I booked for me and my family. ITN showed K availability, but NWA.com and the NWA res agent was not able to book it. The hitch was the ticket for my 10 month old daughter. I wanted to purhcase her a seat, and the infant in seat discount was not available in the K class fare. So the computer put us all in "V" class at $400 a pop.

The res agent changed my daughter from infant in seat to adult and volia, we received K class seats at $200 each.