Perk system is designed to control use of planes that would be unbalancing to gameplay without them.
Hence 163, 262, 234, F4u-1c & -4.
There is nothing unbalancing about B26's, 17's, 24's or lancasters.
To have a chance of surviving you must climb above the fight.
Low bombers are meat on the table, period. So if they are sending buffs, up something with a fair turn of speed, lots of cannons and ammo and go hunt.
Easiest 3 kill sorties in the game if you do it right.