My feeling is that documentation is an incorrect reference?
The reference to the USB connection on the D4 and MTP/PTP setting really to me sounds like a cut and paste from older cameras. I think since roughly the D700 no Nikon camera has had this setting any longer. I could be wrong.
It used to be on Nikon's you could choose MTP (or maybe it was PTP) and then if you plugged your camera into a computer via USB wire, your computer could "see" your camera as a disk drive. But that hasn't been an offered setting on recent cameras.