In my experience not all PE upgrades will clear just because A is showing as a promo fare. I've had times where it has, and other times (such as my saga I posted about last year where A class kept appearing overnight every night for 5 days and then kept disappearing) where I lodged upgrades that didn't clear immediately that I then called and they were cleared manually.
In both cases CSRs couldn't understand how I could see there was A class availability just by looking on the Air NZ website.