WM Passive > Specialist(?)

[Tamui]

Hi,

I am wondering about those passives, and if some say WM Passive sucks or Dex sucks...take a look at it closely.
As a Marksman, Dexterity adds 1.5dmg.

Specialist
I use Warmaster LB which is:
118-148(+23)
Also +13 gem
Adding them up makes;
154-184
8% of 154 = 12.52 -> Rounded down -> 12
8% of 184 = 14.72 -> Rounded down -> 14

Therefore this adds more damage to longbow which becomes; 166-198

Warmaster Might
My base dexterity is 91
15% of 91 = 13.65 -> Rounded down -> 13
Since I'm a Marksman this is multiplied by 1.5
So 13 * 1.5 = 19.5 -> Rounded down -> 19
Therefore this adds more damage to my longbow which becomes; 173-203
--------------------------------------------------------------------------
Now this is how I calculated.
Am I missing something?
Can some-one help me?
Or clarify this?
--------------------------------------------------------------------------