Question about Blood Pact

So as my Doom Bolt Conjurer is almost level 75 I am seriously contemplating my skill choices, since there are a lot of skill points and a lot of options.

One of these options is Blood Pact - Wendigo’s Totem Modifier from Shaman mastery. It says “x Vitality damage”. While it’s the same description as Wendigo’s Totem’s I understand that it’s a buff to player’s vitality damage (Totem’s description refers to Totem’s damage). So how is this damage calculated?

I tested it and my sheet Vitality dps doubles, but I don’t see any vitality damage increases in Bloody Pox and Doom Bolt. So where does this “x Vitality damage” go and how does Blood Pact work exactly??

from the game guide on this website:

"Flat vs. Percent Damage
Damage on equipment comes in two forms: Flat Damage and Percent Damage. Flat Damage applies only to your weapon attacks and does not increase the damage from your skills unless they include a % Weapon Damage component. If found on a weapon, the Flat Damage bonus applies only to that weapon.

Percent Damage bonuses affect all damage dealt of that type, which includes skills and weapon attacks. So if you have a 20% bonus to Fire Damage, all of your fire-based skills will do increased damage, as well as any fire damage you deal on weapon attacks."

The guide specifies flat damage on equipment, but flat damage on buffs like blood pact works exactly the same way. Take some time to peruse the game guide if you’re uncertain about basic mechanics

So are you saying that Blood Pact is basically useless for Chaos/Vitality caster? (outside of Chaos Strike)

What about flat damage on devotions? Flat damage from Possession?

flat damage does nothing for spells that don’t factor in weapon damage. period. It never has. If it did, you’d see aether ray and panetti’s builds stacking flat damage

Blood pact only boosts your vitality damage by a percent, but it doesn’t add the flat damage to your spell’s damage.

So it would be useful for some kind of exotic Vitality DW melee Conjurer. I understand.