Don't know what UA procedures are. Working for a major EU carrier we received the flightplan (weight/fuel calc) about 30-45 min before departure. This gives a pretty good idea about T/O performance. After pax checkin completed we received the loadsheet.
Most of the time only minor changes.
Anyhow, a gross mismatch like not taking in to account a complete pax section would have been noticed by the pilots, ehhrrrm most probably.
