Dear Oscar,
Please make sure that the last few first class or business first class seats are not filled by upgrades until a few hours (e.g. 6 hours) before departure, so to provide those paid customers, who are willing to stick to flying UA, a chance to either buy or switch to those seats at last minute.
Currently on major routes (TCON, TOcean), too many times, first class or BF class are sold out more than 24 hours before flight time.
Thank you!