I know the topic of CASE II has been errata'd before and I read those conversations before I posted. I didn't see where this question was addressed but I apologize in advance if this is a Duh! question.
For BV calcs, the rule from Tac Ops Errata:
No reduction is made to the Defensive Battle Rating for ammunition or Gauss weapons mounted in the same location as CASE II, or one location out per the Damage Transfer Diagram (excepting the legs).
If an Inner Sphere mech has an XL engine , CASE II in the CT, and ammo in a side torso, would the exploding ammo penalty not count for the side torso ammo even though it would take the mech 'out' if that ammo went off? Admittedly, that is lousy design but just for clarification, I thought I would ask.