Sigil of Consumption + dmg Devotion Skill = more heal?

Hi, I have a question related to the Sigil and bound Devotion skills. When a skill gets triggered by the sigil,

  1. will its damage add to the total dmg and then 33% get converted to life or
  2. will another 33% from devotion skill damage get converted to life or
  3. will the sigil always convert its “own” damage only no matter what skill is bound to it?

Only sigil damage

thank you.