Air New Zealand Air Points - Upgrading AKL-PPT - worth it?

Looking at the UA *A upgrade chart, I see that if I upfare our trip between AKL and PPT, I can upgrade for 15K each way. The upfare from our current H/M to B/B would be NZ$340 (approx. US$215). In your opinion, is the Business Class experience on the 767 enough better to warrant the cost?

I haven't checked availability yet, so this is just a hypothetical exercise for the moment.

Thanks.

Difference - more legroom (you should have access to space+ zone in economy), much more recline (is your flight a daytime one or nighttime?), marginally wider seat, more padding, better food & drink, less wait for f&b service. Through your *G status you already have lounge access, extra baggage allowance.

Note sometimes 777 is used on the route - with the flat Business Premier suites.

Outbound is 10:00 - 16:00 and return is 01:50 - 06:55. On NZ, is upgrade availability the same as award availability? Currently, only the outbound shows any Business Class availability on ANA (that's the segment we had to book into M).