My personal view on fitted for but not with is that if you don't have the the gear to fit quickly in the time of crises it is a waste of time. While the evolved Mogami seems to be the logical choice getting 3 plus 3 opvs past treasury is is very unlikely. I would think that currently, getting 3 of anything past treasury is a long shot. with the T31 type being quoted as significantly cheaper this may be the option we are stuck with and only 2 due to treasury,I know the Mogami is not confirmed yet, but I wonder if it's worth NZ considering buying a Mogami as the OPV replacement as well, in a "fitted for, but not with" configuration . The very lower crew size for the fully speced version means the OPV version would need even less crew- No missiles, just a few guns. It'd have exceptional range, outstanding logistics savings. In case this sounds ridiculous, just consider China already uses 10,000 ton "Coast Guard ships", and this would allow NZ to bolster naval firepower relatively quickly. eg 3 Evolved Mogami, 3 OPV versions of Evolved Mogami.
A friend of mine who was part of the ANZAC team has told m of the struggles they had with treasury to get anything fitted to them as treasury tried to get just about everything they could deleted including the gas turbines on the bases that the turbine was only needed to go fast and they only had to go fast a small percentage of the time. The reality is that treasury has huge influence and very little knowledge or common sense when it comes to defence.