It really needs to be programmed to hold the U space until gate time on a 2+ reservation if U=1 AND FC open seats is >2. Or some method. If >1 then skip. If you have a paid FC seat at this point, there is almost never space to do one anymore, because they clear the upgrade list so early as it is. None of this is new, but for Alaska using FC as a retention tool vs Revenue Generation, they sure do not implement it well.