It is all based on the awards that you win. Each one has a value. It looks like you should have gotten the winner(75), structures (15), deaths (15), gold (10), kills (15), and kill streak (15). If I had to guess I would say you got two kills right as the map ended (after the cit fell) and they didn't count towards awards. This caused the UB to beat you on kills and kill streak.
The awards you missed were kills(15), kill streak(15), assists (15), reinforcements(15), damage(15), flags (15), and citadel upgrades (15). QoT probably got assists, damage, and reinforcements (for 120). UB probably got flags, citadel upgrades, deaths, kills, and kill streak (for 150).
If you get kills after the citadel falls when you do like 2k/hit, they don't count towards any awards because awards are calculated right as the citadel falls (or whatever completion criteria the map is set to).The kills or deaths do show up on the final scoreboard however. Hopefully that helps clear things up.