Thank you for clarifying, I've emailed the schools aswell as QTAC to make sureGEMSAS covers 10 graduate schools and uses 50/60/70/80 for 4/5/6/7.
For the undergrad med/dent schools GPA calculation is done by the TACs (UAC QTAC VTAC etc). They generally use P/Cr/D/HD for 4/5/6/7 and ignore the numeric marks.
Since NZ unis use A-/A/A+ instead of P/Cr/D/HD we don't know for sure how the TACs calculate. It's only our speculation that they might use 50/65/75/85 for 4/5/6/7, since this is the grades scale used by the UAC/QTAC unis.