Anachron.... Apparently you do not read up much about WC3...
Battlenet said:
For positive Armor, damage reduction =((armor)*0.06)/(1+0.06*(armor))
For negative Armor, it is damage increase = 2-0.94^(-armor) since you take more damage for negative armor scores.
A Positive Armor of 1 reduces damage by about 5.7%. A negative armor of 10 increases damage by 46.1%. A unit with 20 armor basically has 55% extra hitpoints -- 100 would become effectively 155.
The source article has been vandalized as 20 armor grants more than 50% damage reduction and thus allows the unit to take double damage (over 100% more hits as each does half damage). It used to be right but has been changed to be incorrect for some stupid reason, the formula is right though.
20 armor grants 120% more equivelent HP.
100 armor grants 600% more equivelent HP.
You however are completly wrong...
Formula for damage reduction...
damage reduction =((armor)*0.06)/(1+0.06*(armor))
damage reduction = armor / (50/3 + armor)
damage reduction = (3/50) / ((3/50) + armor)
(3/50) = a constant = 0.06
Formula for damage multiplyer
damage multiplyer = 1 - (3 / (3 + 50*armor))
damage multiplyer = ((3 + 50*armor) - 3) / (3 + 50*armor)
damage multiplyer = (50*armor) / (3 + 50*armor)
damage multiplyer = armor / (3/50 + armor)
damage multiplyer = (50/3) / ((50/3) + armor)
(50/3) = a constant = 16.666666666666666666666666666667
Formula for equivelent extra hitpoints
extra hp = ((50/3) + armor) / (50/3)
99% damage reduction is 1650 armor
Ofcourse this is all subject to armor multiplyer changed from game play constants but this was the usual melee armor behaviour.