Yes, we found the info pretty poor as well. I have a certificate in management from the OU which I have been told is a level 5 - I think it depends where your qualification is from as well. We have had to pay for pre-assessment for my husbands qualifications (degrees but not from any of the places listed) and are now having to pay for full assessment. Not cheap.
I found that emailing NZQA directly was more helpful - perhaps you could try that route.
http://www.nzqa.govt.nz/
Hope this helps
Regards