Data points: I'm EXP with Gold companion on same reservation. Requested upgrade at booking, 3 months out.
- 12/23 CLT-TPA on LUS A320
T-100, 9/12 open in F on seatmap
T-48, 8/12 open in F on seatmap
T-24, 8/12 open in F on seatmap
Both Upgraded 4 hours prior to flight. After upgrade, 6/12 still were open.
- 12/26 TPA-CLT on LUS A321
T-100, 16/16 open in F on seatmap
T-48, 16/16 open in F on seatmap
T-24, 15/16 open in F on seatmap
T-6, 14/16 open in F on seatmap
Both upgraded 5 hours out. After upgrade, 11/16 were still open on seat map.
100-hour window has gone the way of the Dodo, my friends.