HT or Pyro:
When first announced, the "Perk Philosophy" was:
"The perk system is a way for us to introduce some interesting but otherwise unbalancing planes on a limited basis but the benefits go deeper than that.
Perk planes (and vehicles) would be things like Me 262s, Ta 152s, Tempests, B-29s, Ar 234s, Tiger IIs, etc. These are interesting rides but would be very unbalancing if they were available on an unlimited basis....
Points are awarded for both kills and damaging and destroying enemy targets. This in turn is weighted by the type of plane that you and your opposition are using. Flying the less popular planes will get you more points whether you are in air-to-air or air-to-ground mode.
Likewise, the higher quality the planes of your opposition, the more points you get for them. If you shoot down lower quality planes with higher quality ones, you don't get much for doing that but you do get a lot for the exact opposite."
The emphasis was placed on the "quality" of your opposition. I believe this was construed by most players as a reference to the "historical" performance capabilities of a particular aircraft.
Was that an incorrect assessment?
Further this statement points out that "Flying the less popular planes will get you more points" and thus implies that the converse is also true. Flying the more popular planes will earn you fewer points.
The "popularity" aspect of an aircraft is not (in this initial philosophy) related to the plane's "perk cost" (availability) but rather how many perk points one receives when either killing or being killed with respect to a particluar aircraft.
Nowhere in the original official HTC description of the perk system do I see "Popularity" as a factor in determining "perk status". Rather, it is only a modifier in EARNING "perk points."
Anyway, later (on 1/6/01) Pyro altered that situation in a post on the BBS. He said:
"Perks are a way to balance the arena, not so much a means of classifying planes. How many were produced or what its combat record was is not relevant. Some planes intended to be perks may not need to be while others that weren't intended to be may end up getting perked.
Right now, the F4U-1C is accounting for about 20% of all kills in the arena. I don't want to push the score values any further so perking it is about the only option left. I don't really like the idea of making a carrier plane unavailable from the carrier."
So now, has a philosophical change been made to "Popularity = Quality"?
The Spitfire/Seafire situation seems to indicate that the new ENY formula relies primarily (if not totally) on useage. The Seafire is at 25 while the Spit V is at 35. Basically, this is the same aircraft with respect to performance. The introduction of the CV has altered the popularity factor, however.
If so, this is clearly a change in the published HTC "perk philosophy".
Could either of you guys clear up the intent of the perk system? I'd appreciate it.
Either way, it probably won't affect me. Either -51D or the -47D will probably always be available unperked.

Thanks!