It's a weird one for Airnz - I've noticed the mandatory full dimming (completely black) with the newer 789's on a number of NA west coast - AKL flights over the last year. I can kind of see why you might need to do this on the outbound (AKL-YVR etc) as especially in the northern summer it will get light relatively early into the flight, but for inbound toward AKL there really doesn't seem much point as even right in the middle of the southern hemisphere summer these flights are in full darkness until quite close to AKL, about the time when you want everyone awake and seat belts on etc. For the majority of the year it's still well dark upon touchdown.