Considering that A single KV8 burns a whole faction in the blink of an eye, why should ir be excluded from the limit? Does the IS2 need support by 2 broken flamers? The KV8 needs to be delayed to 12 CP and only one in game, same as the crocodile.
If you opponent has gone Shock Rifle and is spending his fuel on two KV-8s and then an IS-2 I have to ask what sort of armour you have that can't handle the IS-2, as the KV-8s will contribute basically nothing to an armour battle