My mother’s general visitor visa was just approved and these are the conditions :

Travel conditions:
The start date of your visa is: 08-December-2022
Your visa has Multiple entry conditions
The last date you may travel and enter/re-enter New Zealand is: 07-December-2023

Visa conditions
Return/onward ticket not required.
Stay subject to grant of entry permission.
The holder shall not undertake employment in NZ. The holder shall not study for more than 3 months in every 12 month period in NZ.
This visa expires 6 month(s) after each arrival.

My question is : is her visa valid for 6 months or 12 months? Meaning say if she enters NZ tomorrow, can she stay in NZ till about May 2023 and then leave for a month or so and then come back again in August and stay till late November 2023? Or does her visa expire in June 2023 if she enters in December 2022 and she will need to apply for a new visa again?

Sorry if my question sounds a bit silly but I was of the understanding that visitor visa was only valid for a maximum of 9 months. She’s been here several times pre COVID and these conditions are different to her previous ones. So just looking to clarify that.