That LAN flight is not to be trusted! A colleague tried the same trick Syd-Akl. Flight is mayhem with a very poor punctuality record, potentially enough to spoil trip. Go for it only in a spirit of adventure.
I'd look into switching to EK for that last Syd-Akl hop. F available on the 388 (showers etc.) and it's just long enough to have a laugh. I do not know how the times align, mind.