Key point to me is what you actually asked for - and the terminology becomes important - as intimated by others.
Whether you asked for a reissued ticket in business class (seems not according to Air NZ), or purchased a ‘cabin upgrade’ which would only ever earn points at the rate of the PE fare. The price difference may not be much ( it all depends), but the pointsvearn significantly different.
Your receipt should be useful to see what, exactly, was purchased.