Except I do have a FCM offer on the SEA-FAI flight ($149.43 -- it doesn't show in my screenshot), just not the DTW-SEA segment. Like I said, I don't really care that much and it certainly makes sense to hold back at least some seats if you anticipate FC purchases from new pax. I also understand why FCM offers can be more than fare difference if you think about sunk costs with employer paid tickets (where upfaring will not actually save you, the flyer, any money).