understanding damage

[Nikkentobi]

I'm running an oracle with an electricity based staff. I've 2 achilles relics, one's bonus is +20% damage and the other is +25% attack speed.

i'm wondering what the +20% damage is based on. Does it counts toward my staff's base electric damage? or total damage that i deal to enemy (this is what i hope, but just feels too good to be true)? or what i fear the most, that it only counts towards "normal" damage such as dealt by melee weapons?

Anyone can help clarify this to me?

[Zukker]

afaik %damage counts only towards "normal" damage. The modifiers you need to boost your damage made by your staff is %elemental damage