NutLoose,
More research confirms that the two CC3 aircraft were built and certificated as 146 QCs. (cf #13).
The play on words - 'no cost', could be seen as no additional (external) cost above a new role for which the aircraft is suited to undertake as a multi role, quick change aircraft..
The headline medical role could represent the in-house adaptation (JADTEU) of existing medical cabin modules used in other, older, aircraft types, by fitting the equipment onto self contained, quick-change pallets, opposed to requiring cabin refits on other aircraft.
Thus 'cost' is no more than a normal adaption and change of operational roles, for which the aircraft is ideal. Bean counters might play with offset cost-saving on other types, or increased productivity in their roles - more tanker capability, (or aircraft for HRH / Government use).