I ran into this problem while I was testing out the combat system. APDS ammo just isn't good, which is a shame as it's been a mainstay for as long as I can remember. Michael's optional rule is pretty good, but it doesn't totally encompass the function of APDS ammo. Negating 2 hits of Hardened Armor is nice, but it does nothing against "normal" armored targets, which objectively is the point of the APDS round. Just remove the -1 DV and it works the way the system and the ammo is supposed to (Attack Rating representing increased armor penetration).