Also, in regards to the ZIP System used on TOH Bedford. If you were all paying attention, in the addition in which they installed the zip system sheathing on the addition, they ALSO installed felt paper over it. You'll note that they never mentioned that on the episode, but it's clearly visible in the scene where Norm/Tom were walking around the outside of the house. I find that interesting becauses Huber (the maker of zip system) claims that no felt paper or WRB barrier such as tyvek is needed with zip, simply attach the sheathing, tape the joints and you're ready for shingles or clapboards. My guess is that TOH is leary of the long term success of ZIP and thus they went through the added (and I think smart) step of adding the felt paper, which is simply another layer of protection.
My personal opinion is that if you're building a house with zip system, make the investment in adding the felt or house wrap as well.