If those prices are right then the Japanese are really starting to get their act together.
Maybe, maybe not. They are getting their act together with respect to the aircraft itself, but the prices are not yet there. They have a target price of getting it down to JPY14.4B per unit (NZD$175m) once production builds up beyond the initial 20 airframes - but whether that can be achieved remains to be seen. The current C-2 price (NZD$230m) as delivered is very likely to be a MDE acquisition price paid by the Japanese MinDef to KHI without inclusion of a training, infrastructure, spares, support & sustainment package.
As a contrast the contracted price for Luxembourg's sole A400M with the Airbus Consortium including initial training and support and was Eur168m or USD$178m for a 2019 delivery. Also the all up revised budget for the 22 RAF A400M's is £3.75B including training, infrastructure, spares, global support & sustainment, or effectively £170m per unit or USD$207m. The MDE acquisition price that the RAF paid was around £132m per unit or USD$162m (Up from the initial £125m due to delays) In my view the training, infrastructure, spares, global support & sustainment price is the real price and going on the UK's A400M acquisition the RNZAF would be looking at least $NZD 290m or $1.45B for the five aircraft. As there is really effectively no great price differential between the A400M as sold to the RAF/Luxembourg or the C-2 delivered to the JASDF as a MDE acquisition, both circa USD$160m, it would come down to who is best able to deliver training, infrastructure, spares, global support & sustainment - I cannot see therefore a C-2 total procurement 'package' being substantially less than what the similar sized A400M can offer. Currently the A400M has its GSP setup for it operators - the C-2 does not. The closeness and traditional ties between the RAF & RNZAF as well as being members of the FPDA (along with Malaysia - another A400M operator and regional participant) is another reason that people should not discard the A400M.
Special 'deals' are problematic because they can be challenged in the WTO, of which NZ and Japan are signatories along with the other competing countries per Brazil and the USA. So called product 'dumping' is seen as anti-competitive practice and can be dealt with harshly. The special sweetener deals would have to come elsewhere within the relationship at a G2G level and not demonstratively part of the 'deal' directly and would be along the lines of reciprocal trade access preferences.