Soviet tank crew survival.

[PlasmaKrab]

Well, that makes for non-pentrating hits, this happens a lot. High-angled shots tend not to penetrate too (whatever your magic silver bullet, if you hit at 83° and have to cross 5 meters of equivalent RHA (that's with 600mm...).

Now about survivability, I think that things like flammable turret hydraulics fluids with internal tanks, or clumsy fuel tanks (think BMP-1 or M-113), maybe even aluminium armour should be integrated into the survivability rating, at lest for the worst cases. If that's posible at all with only 6 levels.
IMHO modern AFVs rise much too quickly to surv=6, which should be kept for targets with really high survivability and plenty of inner spaces like shelter bunkers or blue-water ships.
Just my opinion of course!