Again
Please note that if part of your itinerary involves travel under the piece system, then the piece system will apply to your whole Air New Zealand journey
My understanding of 'itinerary' is the entire routing from departure airport to arrival airport.
My single ticket -FRA-BKK-AKL-NSN-AKL-LAX-FRA - contains to/from/via elements, thus per definition the piece system must apply to the AKL-NSN leg. (It did on the NSN-AKL leg)
@ Tightslot
ID90R2
Single ticket as above
Separate PNRs but as christep correctly points out, PNRs aren't of relevance here.
UPDATE
Air NZ online help confirms that the piece count should have applied on all NZ sectors
Left hand, right hand....?