George they do ask for that here in MA.

More than 9 current carrying conductors through the holes in studs and joists will need derating.

However we also have less a less restrictive derating table.

I understand there is much controversy about this and many areas do not ask this. I can sure see it going either way.

Not much help. [Linked Image]

Bob

Bob Badger
Construction & Maintenance Electrician
Massachusetts