[{quoted}](name=Doctor Jarvis,realm=NA,application-id=3ErqAdtq,discussion-id=3o7no4nE,comment-id=00030001,timestamp=2017-05-20T00:20:15.101+0000)
That's just not true. Adding 400 armor from 400 only increases damage reduction by 8%. If something is coming at you with 1000 points of damage behind it, the difference between 400 and 800 armor is 80 effective health.
I can't remember the examples I used to use, but I will do my best to explain it as clearly and effectively as possible.
Target 1 has 1000 health and 0 armor. The attacker deals 100 damage per second (before armor). 1000 health divided by 100 damage per second is 10 seconds. Target 1 has 10 seconds to live.
Target 2 has 1000 health and 100 armor. The attacker deals 100 damage per second (before armor). 100 armor offers 50% damage reduction. The attacker's actual damage per second is 50. 1000 health divided by 50 damage per second is 20 seconds. Target 2 has 20 seconds to live - an increase of 10 seconds.
Target 3 has 1000 health and 200 armor. The attacker deals 100 damage per second (before armor). 200 armor offers 66% damage reduction. The attacker's actual damage per second is 33. 1000 health divided by 33 damage per second is 30 seconds. Target 3 has 30 seconds to live - an increase of 10 seconds.
Target 4 has 1000 health and 300 armor. The attacker deals 100 damage per second (before armor). 300 armor offers 75% damage reduction. The attacker's actual damage per second is 25. 1000 health divided by 25 damage per second is 40 seconds. Target 4 has 40 second to live - an increase of 10 seconds.
I'm sick of typing all of that out even with clever copying/pasting, but I promise you the trend continues in exactly that way. In the scenario of 1000 health and 100 damage per second, 100 armor will always increase the target's time to live by 10 seconds.