He was talking about shutter count software and shuttercount in a picture, so I assume that it is a real shuttercount and not just camera count.
If the File Sequence Number is Off, the next image you take will be numbered xxx0001. Turn the camera off, and the next image will be xxx0001. Turning the camera off resets the file numbering to 0001. Set the File Sequence Number to On, and images will be numbered sequentially.... xxx0001, xxx0002, xxx0003, regardless of whether you turn the camera off or not.
The shutter count, however, is ALWAYS sequential, and cannot be changed. Nikon does not change (and maybe even cannot) the number even when refurbishing a body.