I had an interesting experience that I thought I'd mention on here about for those who are in the habit of checking flights regularly.
For those who don't know A class is both a PE upgrade booking class as well as a discount PE booking class. If there is A class available for sale on the website it means an A class upgrade can clear into this - however A class can exist as an upgrade class but
not appear as a booking class available for sale on the website.
I booked flights to ADL for a long weekend a couple of months ago and R class for the return was cleared at time of booking. No A class was available at the time but I booked seat only so I could decide closer to the time what I would do in terms of adding a bag or upgrading. I'd never tried Economy on the 789 so even thought I might give it a go.
With a big Aussie sale a few weeks ago I thought I'd see if any A class availability opened up, and looking at this at 7am on a Monday morning A class was showing as available on the Air NZ website. I went to lodge the upgrades a few hours later (split PNRs so needed a phone call to clear the other) and upon checking around 10am the A class had gone and only O was on sale. Thinking that was strange I looked at EF and saw availability and nothing had changed except A had gone.
Tuesday morning comes around and I once again see A class in the Air NZ website and A5 in EF. I was busy so rang Air NZ a couple of hours later to check the fare cost I'd paid - as people will know they (typically) don't charge a booking fee or change fee if you're upgrading to a higher cabin and I suspected the price of my fare over vs the A class fare advertised may have been less than $100 - so it made sense in that case to upgrade to A rather than lodge a $100 Elite APD upgrade. Turns out A class had gone again and wasn't showing on the NZ site or EF.
Wednesday comes around and of course by now I'm really curious (and angry that I keep missing out). A class shows up but I purposely want to see what happens. By mid morning A class had gone from EF and Air NZ website.
Thursday morning comes around and A class is available again. I get stuck on a job first thing and can't get it done in time. By now I've gone from being curious to being angry about this.
Friday comes around and I have an early morning flight to SYD. Lodge upgrades online and call and get them cleared. CSR is pretty much in disbelief that this happens.
I'd had contradictory advice from sources in NZ over the years about whether an upgrade will clear automatically if A/R becomes available and it's probably one of the few things I don't know the correct answer to. This case however that it's worth checking things regularly!