I did many tests with the Lycan Death Mage and noticed that wearing itens with high ability power doesnt affects the skills damage, neither in the buttons tooltip or the floating numbers.

Example: my DoTs in the third skills (magical skill) was 190 in the tooltip and 147 applied to the enemy hero. WITH OR WITHOUT a +469 Ability Power item slotted.

The same with any other abilities.

So, Ability Power for what? What am i missing here?