The Ammo is incredible in the 262. Problem is the ballistics just suck.
Anyways, your not going to see the cost dropped. The reason you are only able to accumulate about 200 perks a month is because you are flying LA's, Spits and Ponys. Switch it up. Instead of the lower ENY above mentioned airplanes, fly their high eny counter parts (LA5, Spit V & 51-B). Airplanes are more than capable, and you will notice a significant increase in perkies