Hmmm... the agents in NAN are very strict about baggage charges, and you're situation is quite unique. Since you have a lot of time, I'd do my best to enquire with Air NZ directly and get a written response from them via e-mail (go to "Contact Us" on airnz.co.nz).

Here's what you're after:

You either need to be booked as a "Works Deluxe" passenger for NAN-AKL (2 bags), or have the agent in NAN recognise your transit in Auckland as a transfer and award you the Business entitlement (3 bags).

Also, unless you're flying via AKL from YVR to NAN, note that your flight is operated by Air Pacific for the Transpac segment.