I sincerely don't think that a max range shot on the ass of a kv-1 should be a guaranteed pen for a p4, but point blank (or a bit out) should be, like so for say a t34/tiger.
I think it should for a couple reasons. The lack of an actual side armor value being one of the bigger ones. If we had actual side armor instead of just a split of rear and frontal, I think flanking would be more predictable for all sides. Fewer rear armor shots that come from the front and vice vrrsa
But by far the biggest reason is tank-phasing. Tanks going right through each other completely ends the flank and is an unholy level of stupid. You can prevent this by stopping behind the tank, but you really shouldn't have to. If you could keep moving at all times it would be much easier to trap the unit you successfully got behind (which is already hard to do)
With what we have now, I feel like tanks shouldn't have to worry about penetration if they are hitting rear armor. It's risky enough as is to flank
P.S. Thank you for actually responding to my point and making your opinion/disagreement on it clear. That's normal for you, but this thread makes me feel compelled to show gratitude for it...