Very interesting Mr. Spotty, I'm curious as to how recent the "working group" you refer to occured. Boeing has been using the term "Flight Deck" in lieu of "cockpit" in their publications since before the first 74 was produced. The department concerned with such things at Boeing is indeed named FLIGHT DECK ENGINEERING and has been for quite some time. Numerous Airbus docs however refer to both. One such doc is, Airbus Cockpit Philosophy by
Captain Etienne Tarnowski, 1999