Air New Zealand Air Points - EF Domestic Fare Class Availability/Price?

How up to date is EF fare prices and availability to AirNZ website? Sometimes it seems like EF says they are available but when you try to book on NZs site they aren't.

E/F gives a view of availability of booked from the USA (or, optionally, the UK).

If you are trying to book from elsewhere, availability/price can indeed vary.