In such cases, the IRD recommends contacting them, if necessary, to confirm the correct PIE information to include in the return.
Tax New Zealand: IR3NR PIE calculation where PIR is not 28%
For non-resident individual returns, PIE/PIR income should be taxed at a PIR of 28%. As advised by the IRD, if the PIR applied is not 28%, the PIE income must be included in the return and will be taxed at the basic rate.