Ah i'd forgotten what that page was.
Assuming its correct, which i'm unsure about, the Fleshpound on 6man Hard (Suicidal) has 4220hp (5900hp) going by 375x5 +1500 xdifficulty. Lvl6 Crossbow headshot is 4320. But then again, the FP *should* have 50% damage reduction for all non-explosives. Then again it should also be impossible to 1shot it on Suicidal but thats whats happening.