Ok guess I'm getting messed on terminology. I didn't mean vertical studs, I meant the blocks you were talking about. I still don't see that as fixing the problem with the bulkhead though because the door wall is within 4 feet against an exterior wall (ie., a spot where minimal flexing is anticipated), whereas the bulkhead corner is at least two joists away and within a couple of feet of the centre of the joist (ie., a spot where maximum flexing is anticipated). The more I read about sister joists however, and couple that with some cross-bracing, makes me think that there is merit in at least trying that before undoing all my framing ...
