Good answers gents!
Personally, I don't know the real answer...
So far, though:
- 5 joist or stud layout alternative to 24"(4), or 16"(6) per 8' (Most logical answer)
- Truss layout (Not mentioned here)
- And the "Stanley Cubit" (Pete was not alone on this, there are many who prescribe to the same therory. *More on this in a minute...)
- My favorite so far, and related to the one above. "It's a Masonic Order thing... You wouldn't understand."
*Asked around to a bunch of old framers who note that it must have been around for some time, because they only ever see this lay out used in baloon frames in the early 1900's and prior. Well before plywood and sheet-rock, back when '2X4's' were 2X4".
Anyway, at this point, I think this is a Myth Busters Issue.