The reason for this is because Starfire's cooldown is 0.4 seconds and witherhoard's direct hit tick rate is 0.5 seconds meaning it's not regening at the fastest rate with only a witherhoard. Shooting the trace just allows you to proc starfire's perk immediately off cooldown saving a tenth of a second per proc.
No. We tested all raid mods that increased damage in some way and they all either didn't function properly or weren't applicable here. Just a side note, the cabal extinguisher mod buff goes away when you yourself gets either the field of light or flux of darkness buff.
