Mike:
Matthew's answer is pretty close to the mark. I am certain that Mike did not want to be perceived as "copying" Sand Hills' approach, even though he respected it tremendously. And in point of fact, both David Kidd and I approached Mike (instead of the other way around) back in 1994-95, and I think we were rewarded for our initiative.
I can also tell you for certain that when we were building the second course, Mike was not yet seriously thinking about the third. I really don't think that at the start of the operation he had so much confidence that he would "save" Bill & Ben for a third course, because who would have bet there would ever BE a third course?
I do think that for the fourth course (presumed to be the worst site of the four, although opinions differ
) Mike was uncertain that any living designer could take the fourth best site and produce something equal to the first three courses ... that's partly how he got the idea to hire C.B. Macdonald.