Hi Brian, yes that is the situation, thanks for your reply.
I guess I could list them as separate albums, but this is mostly just an issue with deluxe/super deluxe editions where the main album (disc one) might be mastered well, but the bonus material on disc two/three is brickwalled (like some of the Smashing Pumpkins recent reissues). This causes the main album on disc one to play at a lower average volume than it should because disc two is so loud and is being used in the volume averaging. I guess I could break that bonus material out, but I'd really prefer not to.
iVolume (a third-party utility for iTunes) used to have an option where I could check a box to apply the album volume leveling on a per disc basis. Was just curious if that existed in MC already (looks like not), or if it might be an easy option to add?