[JaM]

You need to think in game terms. Heat penetration works different.Round with pen 31 will penetrate armor with armor 30(it is possible penetrate even 31). Game counts with weak spot hits, as you know, it gives + bonus penetration (it happends mainly durng close range fire) so we should forget about all those RPG penetrating thru the cage.Bonus +33 will make IFV with SLAT more resistant to RPG fire (as it is in real),tank HEAT round will be affected too, but you are not able choose ammo, game choses instead, so tanks will use AP rounds against target witch is imune to HEAT fire.