I do the same: PE plus upgrades.
Just be aware that as an NZ frequent flyer your points / status return for cash is usually better buying a Business Class ticket from bestflights.com.au on a different Star Alliance carrier.
The best current fares INCLUSIVE of all taxes are:
Air China = $5579
Thai to BKK, then SAS to Europe = $5799.
Thai to BKK, then Swiss to Europe = $5639.
An Air NZ Premium Economy ticket will earn 330 Status Points and 310 Airpoints.
The Asian Business Class options earn 630 Status Points and 530 Airpoints.
I typically pay around $5400 for Premium Economy on Air NZ to LHR - it makes sense only if I want a stopover at LAX.