I wonder, by the way, which is more unrealistic: blowing up an APC with rifle bullets, or the similar "cumulative" effect of RPG's. I think, that an RPG either penetrates the armour, or not. If not, then it does little or no damage to the tank, and then, the next RPG does not destroy it any easier. But like you said, this is probably not the worst flaw of OFP/ArmA.