Instead of adding 3% to your Deflection Severity, it adds 3% of your existing value (according to tooltip...)
50% Deflection Severity becomes 50.7%. As katbozejziemi points out, that doesn't even appear to make sense.
I admit that it's within the realm of possibility that this was intentional, but two facts suggest to me that this is a bug:
A) This is such a weak benefit that I can't believe it was intended to work this way.
Critical Severity does not work this way; it adds flat % to the value. Seems logical to assume that Deflection Severity would work similarly.
Also makes me wonder if new feats that increase Deflection Severity are working this way as well.
Comments
True. I have no idea how their math is working, here. Updating original report to reflect the fact that the bug is bugged :P
In the tooltip it indicates that your Deflection Severity is operating at 100% of normal value and that 3% is modified by features. It looks like the game is dividing that value by your existing Deflection Severity %...?
So 50% value of 3% would be 1.5%, which would modify existing severity % to be 50.7%? How do they come up with this? :P
Contagion - Cleric
Testament - Wizard
Pestilence - Ranger
Dominion - Paladin
NIGHTSWATCH
Iyon the Dark
Given that this is the exact current tooltip of Illusion Shimmer, "You gain 3% Deflection Severity.", what were your results and are you referring to combat log testing or just Character Sheet tooltip?
Iyon the Dark
Incorrect.
Character Sheet tooltip change is from 50% to 50.7%. These are my results that are consistent with the Character Sheet:
GWF with 54.7% Damage Resistance.
Deflection WITHOUT Illusion Shimmer:
i.e. 304/1345 = 22.6% reduced damage.
Deflection WITH Illusion Shimmer:
i.e. 306/1374 = 22.3% reduced damage.
Working from the stats themselves,
Normal: (1 - 54.7%) x (1 - 50%) = 22.6%
Current bugged boon: (1 - 54.7%) x (1 - 50.7%) = 22.3%
Tooltip correct boon: (1 - 54.7%) x (1 - 53%) = 21.3%.
So, under no circumstance is the boon working according to its description.
In addition, at the moment for me that boon with 20% Deflection Chance would represent 20% x 0.3% = 0.06% overall damage reduction buff. Even if corrected, it would represent 20% x 1.3% = 0.26% overall damage reduction buff... which, no matter how you look at it, is very poor indeed.
CAVEAT: this was tested on Preview version NW.14.20140123a.1.
denoting the mitigation of 3/4 of the incoming damage as 300% deflection is somewhat backwards, but yes, without deflection, you would have taken 400% of what you did take.
it is under this strange math that they apply the boon.
lets assume a TR would take 1000 damage, but deflect it, leading to 250 damage without the Illusionary Shimmer Boon.
now to take 250 damage while deflecting with the Boon, the TR would have to take 250 + (250 * (300% + 3%)) damage (300 is the normal 75% deflection, 3% is the boon. so thats 250 + 250*3,03 = 250 + 757,5 = 1007,5.
now if you look at the 250 as a % of 1007,5 you get something around 24,8%, or in other words, 75,2% of the 1007,5 are missing.
I have half Blue and T1 gear and one artifact and green companions
Indeed that seems to be the math they use. For a non-TR, the "Base Deflection Mitigation" is 200%, boon increases it to 203%, then the deflection severity is calculated as 100*(1-100/203)=50.7. The tooltip is totally misleading as it says the deflection severity itself will be increased by 3% implying 53%. This really will not be too strong and 50.7 is indeed way too weak. They should definitely fix this.
.