All supers should be set to default of Obsidian Mind's (reward for super use efficiency)
If you're good at using your super or producing orbs, you should be rewarded with accelerated super gain for your next super charge depending on how many orbs you make during your previous super like Obsidian Mind. I love that feature to the helmet.
Though the Obsidian Mind rewards you per kill, I believe it should reward you based on the orbs you've created.
Why?
So with Obsidian Mind you are rewarded more for killing a pack of 7 thralls than 2 Captain Majors. Though, 2 Captain Majors would create more orbs than the 7 thrall. Bigger reward for priority targets on the battlefield.
-2 cents