It sounds like a beautiful view, Bruce, however I've got one home in the sheathing stage, and another to break ground soon, so I'm pretty tied down.
Something we haven't touched on so far is the applicable buiding codes in your area; could this be part of the reason she's specifying the spacing/sheathing? If it were a code issue, though, I'd think that 7/16" OSB sheathing and 24" o.c. would have you covered, but it would all depend on the code for that area. In part, the need for 16" centers may also have to do with the roof structure, or if this is a 2-story home, or other reasoning.
Let us know what you find out from her, if you would; we "regulars" are here to help, but we enjoy learning here, too. Best of luck!