The NPAS management have played it close to their chest so far. However, unless they plan to have a box of "resting pilots" ready for immediate action (unlikely if you are to try to save money) I would venture that the system will require fewer pilots.
I am a little removed from this coal face these days, but the picture is rather complicated at present. Prior to NPAS, pilots were self-employed, employed by contractors or be directly employed by a police force/service. These all hinge on contractual arrangements that are between different organisations, that were planned to run for different periods.
No doubt when the final setup is in place, some sort of standardisation will occur. However,that won't be easy. If one assumes that NPAS will not want to directly employ, there could be a nice contract available for one of the big operators to provide and train the pilots.