Further to my previous post, the QANTAS B789 will operate to AKL on QF141 departing SYD at 7:10 and return as QF144 arriving back in SYD at 14:55. Given the current times for QF73/74, the AKL flights could be slotted in, with a few minutes variation, after arrival from SFO and be back in SYD in time for departure to SFO.
Source:
https://www.ausbt.com.au/qantas-boei...ydney-auckland