What about the "without maintaining spacing"?
If you have the NM fanned out so air can freely flow around them they are not bundled for greater than 24". MC and AC may not maintain the spacing because of flexibility, shape and weight, but NM will pretty much stay where you put it in a joist bay between stud bores.
I guess a related question is how big a hole are they boring if they are getting more than 3 NM in here (9 conductors).
