Just got off the phone with my favorite NONEPASS reps on the elite line. I am flying DFW-DTW-AMS this weekend in full Y and wanted to upgrade with miles through CO. I call, they so sorry no seats available. I say ok, but I checked the internet and it said seats are available. She says tough.
So.... I call the supernice Gold Line people at NW and ask for the same upgrade. She taps in her computer and rattles off EIGHT, yes EIGHT available seats for upgrade. I plan on cashing out the last of my CO miles and sticking strictly to the super nice people at NW.