I'm a 21 sorc and I have the same dmg with or without Loki, and Loki 'gives 15% dmg'

I can't understand >.< with my wrathjaw I win 10dmg (gives 20 int)

Bug or something else?? That seems dont raise the damage vinculated to Inteligence -.- I've lost a lot of gold...

I would like to fix it soon! =(

Thank you!