No, but neither does using 4x6's as deck joists.

I received a couple of statements on another home improvement site. A commenter explained in detail why the new design would be preferred over the original design. I've seen several sites that discuss decking explain why 4x6 joists on the ground should be used (for a ground deck) - which was our original design. If you have specific concerns @millworkman - I'd like to hear your thoughts.

I would use 2x6's - 12" O.C. before I would use 4x6's. In my opinion there is absolutely nothing to be gained by using 4x6's, and only money spent.