I grew up in an archery shop making arrows and trying to make them work better. My old man was an archer and an aeronautical engineer and everytime I made up something where I tried putting flaps on vanes (like the NAP) or making a drastic helical , he would always tell me why it would not work.
When ever you use flaps or increase helical to make an arrow spin faster, you also drastically increase the wind resistance which will make noise and slow the arrow down faster and make it lose trajectory.
He would then always give me the example of our old piper cub, when we wanted to slow down to land the plane we would extend the flaps.
when this was done you would feel a tug on your seatbelt from the deacceleration and then the plane would quickly lose altitude.
you feel the same thing when a passanger plane puts the flaps out to land.
All those little flaps on the NAP vanes do is make the arrow spin a little faster, but you lose trajectory, increase noise, and lose penetration because of the speed loss. and you pay about $2.00 for three of them.
Pay more and get less!!!
I have shot and tested a lot of arrows since I learned to shoot back in 1951 and there have been a lot of innovations that have improved archery flight, the NAP just does not cut it.