Was told by ANZ staff that as soon as Qantas exited that route in 2012, ANZ put an extra 777 on per day and filled it.
NZ moved NZ5/6 to daily, along with introducing NZ3/4 a couple time a week.
Currently NZ flies AKL-LAX 18x weekly during the peak season, typically 14x 77W and 4x 772. Approximately 6200 seats every week, each way.