Excellent presentation, Innominate.
In general I don't like perk points, but I concede their value in keeping the playing field from distorting to the point of no fun anymore.
Maybe the A-20 shouldn't be penalized since jabo is what it was designed for. Same for the Ju-88 in the attack role.
Probably better to perk all the bombs for jabos. Otherwise later jabos could still swarm bases with lighter bombs that can take out stuff like fuel and ack and, cumulatively, larger targets too.
Might want to start, however, with lighter perk cost for planes heavily used in real life as jabo, e.g., P-47, Corsair. Keep the highest cost for planes not often used as jabo in WWII, e.g., P-51, P-38 (even though the latter were sometimes used as level bombers, bombing on the lead plane's drop).
Would have to be careful to equitably apply this principle to non-U.S. aircraft whose jabo employment is less widely understood, e.g. some FW models might be more attack than interceptor.
Your idea could go a long way in restoring in Aces High a more realistic and enjoyable balance of the main ways most WWII aircraft were used.