Having looked at the original post more carefully, I think you are correct that this would work (although, like RMB1, I would have much preferred a Hesitation Mitchell, rather than the given movement in which players only play 2/3 or 3/4 of the boards in circulation). However it's not the solution specified in the law book for this situation, and I think a NS pair who seemed to have had a good unopposed auction to the top spot (or were well on the way to it) would be entitled to feel aggrieved if they then lost the board because the director decided to improvise.