330.30(D) Unsupported Cables.
Type MC cable shall be permitted to be unsupported where the cable:
(2) Is not more than 1.8 m (6 ft) in length from the last point of cable support to the point of connection to a luminaries (lighting fixture) or other piece of electrical equipment and the cable and point of connection are within an accessible ceiling.
For the purpose of this section, Type MC cable fittings shall be permitted as a means of cable support.
Some interpret the last sentence as allowing the support up to 6 feet from each fitting to permit 11 feet, 6 inches of cable from a box to a luminaries without support.