For metal, you have to get the bass just right. What works in a bedroom low-level dial-in will not work on stage. Why do many metal players use a tube screamer in front of the amp? Precisely to cut the lows and add mids and tighten up the amps' response. I'd still use a cut at 100Hz. If you are using a 4x12 IR it's adding WHOMP as well.
Remember, if you and the bass player are both pumping out low D/C# chugs that are around at 70-80Hz together, it's going to sound like mud and not clear. So for metal I may go lower on LO CUT, but once you get under 100Hz you are starting to compete directly with the bass frequencies AND your FRFR/amp's sound will become dominated by the low frequencies and accordingly you will lose the focus of the mids and highs. You are trying to slot right between the bass and the snare drum, frequency wise -- fill that up. That's mids and hi-mids, not lows the bass covers.
So it is tricky for metal I agree, and others can chime in here, but that's my two cents. I've had Mark of Periphery over here helping me dial in a few amp tonepack sounds before and he taught me some stuff he likes and I'm telling you he's not putting out frequencies under 80-100Hz at all to get his great modern metal sound...