Answering this would require access to proprietary information which no air carrier would ever release, namely load factors.
How many people are there and paying what fare and what else is there to be done with the aircraft?
Lots of pax, paying full F/Y and an aircraft that can turn back to LAX or go onward with the same load means a later flight is likely supportable. Then, it's a question of whether that aircraft makes more for US elsewhere.