Jenny -
The decision as to whether or not imported whole-leaf tobacco needs (for reasons of biosecurity) to be 'heat treated' is made by MPI (Ministry for Primary Industries) when it crosses the border through Customs.
There was a time when sometimes a consignment of tobacco passed through, unscathed, and sometimes it didn't. Nowadays, however, it seems that it is withheld for treatment pretty much every time.
They basically charge you $45 for them to 'cook' your tobacco inside its package. The treatment darkens it and, in my opinion definitely changes its quality for the worse.
You pay the $45 fee whether they test one pound or (say) ten pounds.
When the new regulations come into being in September they will add considerably to anyone importing a single pound of whole-leaf.
It will look something like this -
1. WLT tobacco and freight.(For 1 pound $NZ63.17) Note; Even one pound will include tax because it exceeds the $60 threshhold.
2.An 'Import Entry Transaction Fee'. (Total $49.24)
https://www.customs.govt.nz/personal/duty-and-gst/faqs/
3. A (almost certain) Heat Treatment Fee ($45)
4.GST (Sales Tax on the tobacco and freight.) Customs contact the buyer when it's in NZ and pays before it's released. $9.48
Making the cost of 1 pound ....... wait for it .... $166.88
And it gets worse; once you lose 30% in stem wastage the cost of the leaf is around $242 per pound (or $534/kg).
So it's not the GST (Sales Tax) that's exaggerating the cost - it's the $94.24 'administration costs'.
The cost for buying, say 8lbs is a lot cheaper, because you're not paying the Transaction Fee and Heat Treatment eight times over - just once.
Eight pounds of de-stemmed leaf would cost around $205.92 per kilogram, which although probably surprising to Americans, is still considerably cheaper than the $1800/kg you would pay for loose tobacco over the counter in NZ.