Is The Fourth Vow really working with Divine Flesh?

Tried out The fourth Vow + Divine Flesh combination and this feels like armour does not apply to Converted Chaos Damage from Hits.

I had 0% Chaos Res (Not negative, just a zero) and about 80% physical reduction ~23k armour. And when I took Divine Flesh elemental hits became so hard, like its converted to chaos part was not mitigated at all. Tested on 3 different maps, removing and adding Divine Flesh in the middle of the map and felt like I take less elemental damage without Divine Flesh. Is that the case?

I know armour works worse against big hits but damage delta was kinda too much, and if THAT is the case, I don't really know where this chest can be really useful.

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seaman wrote:

Quick example:

10 000 ele dmg

w/o Divine Flesh:
with 75% res you take 2500 dmg
total - 2500 dmg

with Divine Flesh:
5000 dmg with 75% res you take 1250 dmg
5000 dmg with 0% chaos res and armour (armor reduces about a quarter) you take 3750
total - 5000 dmg

Yeah, I understand, I had same calculations.

But why does armor reduce about a quarter? Is't it supposed to, like, reduce the same percent as for phys. dmg?

"

seaman wrote:

It reduces by the same percentage as for phys damage. 80% is estimated damage reduction against white monster's default hit. 20k armor will block 80% of damage on a hit of about 1000 damage

https://www.poewiki.net/wiki/Armour#Formulas

You need to cap chaos res.
with Divine Flesh and capped chaos res:
5000 dmg with 75% res you take 1250 dmg
5000 dmg with 80% chaos res (1000 dmg) and armour you take 200 dmg (but I'm not sure what counts first, res or armor)
total - 1450 dmg

So, yeah, I have to get a good Chaos Res to get full benifit from Armour. I think, I don't really need to reduce 20% of 50% of hit (60% hit dmg total) to 4% (52% hit dmg total) at the cost of having Vow instead of a decent chest.

My initial idea was to get armour cap instead of chaos res cap and benefit from Divine Flesh but yeah it is what it is.

Thank you!