"you have one weapon that does 120 damage to shields in 20 kT, and another that does 120 damage to hull/armor in 30 kT"
True. 4 DMG/KT is a bit excessive given the shield sapping weapons.
Such are the dangers of adding new damage types without enough play testing
Now that you've drawn my attention to it, the fighter-class APBs also appear to be missing a zero in their costs.
P&N PBW 3.1 R4.zip