Who has said that they want a single type in service?An interesting development for A400, it appears France may buy upto 4 C130J to complement the A400 for inflight refueling and spec ops work, article also states that they are trying to make a AAR capabilty for the C295 as well. See what the frogs do.
Airbus Scrambles To Compete Against France's Planned Buy of 4 C-130s
Whilst the capabilty does not effect the RNZAF for AAR, but does point to it being to big for the specials. So NZ really needs to get this one right 1st go if they want a single type in service.
The NZDF air transport study hasn't been released yet and AFAIK no leaks, so we actually don't know what they are thinking. Personally I would be thinking that they could be looking at a two tier transport system because the non replacement of the Andovers will have been hurting so to speak. It is true that the Andovers were becoming economically unsustainable, however the utilisation of the Hercs to undertake Andover type taskings will have been expensive, or the taskings were not undertaken. Until the study is released and / or it is covered in the DWP we will just have to wait.