Might I ask what rotation you use and whether or not you dip into Defiance at any point? Fell Cleave being a large chunk of our overall DPS (something like 20-25% depending on crits iirc) it's hard to believe that you would produce this result doing only double FC in your berserk window.

In regards to Pre-Infuriate: I believe the purpose now is to have your Berserk window closer(right after the first SE combo) so that it can line up with Battle Litany and Trick Attack for some big juicy Fell Cleaves as well as putting Berserk and various other offensive buffs on CD faster.