Ryan,
I did ask Jeff Sargent of NFPA if he thought 310.15(A)(2)exc. (10 foot or 10% rule) cancelled 334.80's second paragraph, and he answered it would seem that it does.
Plus the fact that up to four cables of small conductors can be bundled without regard for derating anyway. If you do the math, you still will be allowed to connect #14s to a 15 amp cb, #12s to a 20, and #10s to a 30 amp cb.


Earl