Toad, nobody has ever told me why HTC perks planes they way they perk them. As far as I can figure, there can be only 3 reasons.
1. The plane was rare in real life (Ta152, for example)
2. The plane just outperforms every other plane to an overwhelming extent (Me262, Tempest)
3. The plane sees to much usage in the MA (F4U-1c).
Then you have planes that just don't seem to meet the criteria, in my opinion. The Spitfire XIV and F4U-4 are perked planes that are way to expensive, in my opinion. Neither one offers such a drastic improvement over the P-51, La7, 190D9, or 109G10 to justify a perking based on #2. Again, this is just my opinion.