You people are operating on false premise that damage modifier can be included partly to a unit.... it can't.
I suspected it when I wrote my message.
Imo heavy tank and many other mechanisms are doomed to never been balance.
There is an obvious will to represent Tigers or IS2 to be on par with what they were in the reality statistically wise. I mean the only stat that is probably completely different between reality and the game is the range of fire of those tanks, for the rest, armor, speed, turret travers, shell damage etc... are probably varying a bit for balance purposes but they are also reflecting a lot of what they were in reality : Strongs and devastators
Now when you look at mediums, you see where the dev team took most of what was the reality of those tanks far away to design something that suit the in-game design and balance. And the first of all is probably their quantity available for each heavy possibly fielded.
This game is about a story which doesn't really care about mediums, but heavy tank fights.
At the moment, Heavy tanks have no trade off, only a cost when they are available. Opposed to that, mediums have trade of the moment heavies are available, building one more medium will delay the heavy which is better in any ways.
Call me silly but I think old Tiger Ace cost trade off mechanism was the most interesting to evolve and apply to all heavies. Too bad the balance team took the opposite direction.
Second mechanism that should be applied to all "generalist" heavies is the amo switch. Keep the same damage profile but AI shells do only AI damage and AT shells do only AT damage so an opponent that goes combines arms can actually react the kind of shell and put his tanks first or infantry first.