This is contrary to the applicable legislation which is quoted on the NZ Transport Agency web site here.
I have quoted the first part of section 3.8.1 below:
"Applicable legislation: Land Transport Rule: Vehicle Standards Compliance 2002, sections 7.9 and 9
3.8.1 Expiry dates
Expiry date of the WoF
The WoF expiry date is calculated from the reference date. The reference dates are:
For a vehicle with an expired WoF: the date the vehicle passes the inspection
For a vehicle with a current WoF expiring in 14 days or less after the vehicle passes the inspection: the expiry date of the current WoF
For a vehicle with a current WoF expiring in more than 14 days after the vehicle passes the inspection: the date that is 14 days after the vehicle passes the inspection."
This clearly states that the expiry date should be the date of the current WoF if the date is 14 days or less away. Even more interesting, and what I didn't know, was if the current WoF expires more than 14 days from now the new expiry date is 14 days after the vehicle passed its inspection. (I read this as 6 months and 14 days from now.)
Let's stand up for the law and insist your garage follows the legislation. Don't let excuses like it mucks up our WoF renewal letter system put you off. I suspect the garage prefers the new expiry date to always be 6 months from today so you have to come back sooner for your next WoF and so they earn the next WoF fee sooner but perhaps I'm just being a cynic. If your garage refuses to comply with the legislation perhaps it's time to find a new garage.