How useful is the HP increase from improved hardening?

With the new equipment I was interested in how useful some of the new pieces actually are. The first one to catch my attention was improved hardening (IH). Because heavy tanks have a survivability slot and modified configuration seemed a waster of a slot and other people have already shown spall liner is just worse then IH, I wanted to see if I could workout the exact impact it would have on shots to kill for tier 10 vehicles.

NOTE: this is only for tier 10 vehicles, and assuming you are getting shot by tier 10 vehicles

I've managed to put together a google sheet that pulls everything together.
Link: https://drive.google.com/file/d/1PKnQk5KrzFIyb01WsMgloXLHsKxUPV-s/view?usp=sharing

There are 4 tabs total:

• One for all tier 10 heavies mounting it in the survivability slot for 10% health boost
• One for all tier 10 tanks that uses an 8% health boost
• One that looks at all health values between 2000 and 3000 (inclusive) with a 10% health increase
• One that looks at all health values between 1300 and 3000 (inclusive) with a 8% health increase

How I put this together is I assumed only 320, 390, 490 and 750 damage guns are shooting at you since the vast majority of tier 10 vehicles use guns with those rough damage numbers. Using that for each health value between 1300 (lowest tier 10 health) and 3000 (highest tier 10 health) I found every possible permutation (combination) of shots that would kill a tank of that health. I then added the 8%(10%) extra health and found all permutations of shots for that health value. After this I simply subtracted the average shots to kill the non-upgraded tank from the average for the upgraded tank to give how many extra shots on average increasing the health will require.

When it comes to interpreting the numbers the way I see it is you can act like the extra shot average is your chance during a game for IH to be useful in terms of taking an extra hit. The greatest increase in health because of IH is 300 (the maus) so unless you get lucky with a 320 damage gun that low rolls you should only ever expect it to provide a single more hit of HP. What I mean by this is if the average extra shots is 0.5 you can probably expect it to be useful 1 in every 2 games (this is an assumption as there is never a guarantee you will take an extra hit). Taking into account games where surviving for another hit does nothing (surrounded by enemies and it just means a different enemy gets the kill) I would probably say requiring an average of 0.6 would be required before even considering mounting IH. After that you need to consider if you want to run something that will not always be useful, are other equipment options better suited to the tank/provide a better bonus.

Now this data only handles penetrating hits from other tanks, in terms of other usage the extra HP may help mitigate 1-2 shots from artillery rounds (or the odd person firing HE). IH also improves track survivability and repairs so can help on some of the more vulnerable to tracking tanks (or just provide some QoL improvements to game play).

I would say overall the equipment for tier 10 vehicles appears like it will only be useful on heavy tanks to put in the survivability slot and only on tanks with more then 2400 health base. I would definitely say it is a piece of equipment worth considering if you have a spare equipment slot for whatever reason. I would also say there is potential for replacing rammer on something like an e100 as it may allow you to trade hit for hit better in situations where a the engagement is controlled and you don't need to fir immediately all the time.

Overall I would say its not OP and provides some nice side utility on top of being relatively reliable for taking an extra hit in some situations. Probably worth a serious thought on super heavies (primarily e100, 60tp, type 5, 705a because they get high alpha guns for trading) but I wouldn't consider it for non heavies or anything below 2400 health.

Once again this is only for tier 10 vehicles and primarily looks at extra hits due to penetrations fighting other tanks.