To get the 60SC for MEL-AKL-LAX you need a different flight number for the MEL-AKL leg. Of course that would increase the fare, so defeats your purpose. You might be able to find a cheap AS or AA fare out of LAX or the surrounding airports to get 20SCs. LAX-LAS-LAX used to be cheap and easy but not lately, however a fare sale just started yesterday so you should be able to find some MR material.