May be with the Trent issues AirNZ don't want anything that could delay the delivery? Have a bit of time before Chicago flights so need them to cover some 777 time in the shop? There is also the chance it is half installed, e.g. the wiring loom in place and seeing dish not there got a flat panel on the roof opposed to the dome?
With the 777 having high utilisation when are we going to see the 777 pilots timing out? Did see an ad a while back looking for 777 secondments for 787 cabin crew .