Solael's Witchfire mechanic question

This may have been answered before with other skills with similar mechanics, so I apologize ahead of time that I was unable to find the detailed answer i seek.

The skill says: Rank 1
+75 Energy Reserved
0.5 Energy Cost per Second
+8% Vitality Damage
5 Chaos Damage
+1% Attack Speed

My question is about the +8% Vitality Damage. Since the ability itself doesnt seem to have a core Vitality Damage amount, does this bonus actually apply to anything?

IE: My understanding is that if the skill did 100 Vitality damage, the +8% vitality damage would boost that to 108 damage. But since there is no base vitality damage listed, this bonus seems moot. Its not until you pick up the linked skill, Second Rite, at Occultist Rank 25 that you get a base Vitality damage added to the skill. Seems a bit backwards unless im not understanding how the +8% Vitality damage mechanic works.

Any help?

Any buff which can be applied to your buff bar applies to your total stat value.

Say you have +200% Vitality damage. That will bring you to 208%.

Also, the second half of Soliel’s Witchfire, Second Rite, has flat Vitality damage anyway.

Consider this skill a passive buff, i.e. all its % bonuses apply to all other skills and your weapon, all flat damage bonuses to your weapon only.