Clan-based mixed-tech mechs (i.e. experimental mechs with clan chassiss' and IS equipment) are calculating defensive BVs as IS-based mixed tech, when allocating ammo/sauss weapons to arms and rt/lft torso.
I believe a sloution would be to have a Mixed (Clan) and Mixed (IS) choice for the drop-down 'Tech Base' Menu.
Does selecting "Use Clan CASE" from the Equipment Tab (Just below the Targeting Computer) fix the BV issue?
Under the rules of TacOps, there isn't really a "Base" Chassis. Any and every part can be used no matter the technology rating.
So let us know if checking the "Use Clan Case" box works. for the BV issue.