Really- expecting proper grammar from engineers pretending to be lawyers- haven't we learned better by now? :-)
I think that the key word is accessible....remember, the porch/deck/patio is considered "outside" the house- even if they are completely screened in and without any doorway into the yard.
I can imagine a house on sloping ground, where I would understand the code to require a receptacle both at deck level, as well as outside the deck area, nearer the ground.
I would try to solve the question by looking at things from a practical level....where will the hedge trimmers and electric mower get power? Or the TV and electric Bar-B-Q on the deck? Will serving both needs from the same receptacle create additiona hazards- and are there other features that would keep this from happening?
Along these same lines, I think we can dispense with the "in use" cover if the deck has a roof over it.
The details of the deck might also affect my decision as to where to locate the roof-line receptacle for the Xmas lights as well :-)
