extra_energy is incorrect for Ferocious Bite (warriors are the only other ones that even use it). That extra energy isn't affected by any resource reductions.
e.g.
No buffs: Ferocious Bite = 25 + 25 = 50
Berserk: Ferocious Bite = 12.5 + 25 = 37.5 (currently 25 in Ovale)
Clearcasting: Ferocious Bite = 0 + 25 = 25 (currently 25 in Ovale)
Berserk + Clearcasting: = 0 + 25 = 25 (currently 13 in Ovale)

The clearcasting portion is correct, but Berserk shouldn't affect the extra energy.

This seems to be different than say Arms execute which is affected by Battle Cry's 100% rage cost reduction. That and ignore pain seem to be the only ones using a extra_ right now.

Could probably be changed to use the extra_resource modifier from #63 but not really that familiar with how to modify the simcraft translator (other than simple things like adding .cost)

This is actually now incorrect, at least for Ferocious Bite. Blizzard fixed it so that power reductions now affect the extra energy too. I'd be willing to best Ignore Pain is the same way.

I'm actually working on an overhaul of the power code, I have it mostly done in lua, but now I need to go back and make it in typescript.