hi lolcoaster,
In NZ, about a few months ago back to 2015, CX promoted a special fare from Akl to PVG or Beijing via Hk at about NZD 12xx in economy S or N class ticket and you could get 30kg baggage allowance in total by weight system to Shanghai or Beijing as published in the CX website (Normal baggage allowance from Auckland to Hk sector is 1 piece not over 23kg in Y class ). So in your case, as the baggage allowance illustrated in your eticket should be right. But for your security, it is best to email cx quoting your etickt # and cx booking reference for the final confirmation.
Cheers