What are they doing sending holds to a 3.94/178, a 3.9/175, and a 3.97/173? This is the weirdest cycle ever (of all 1 that I've observed).
If I were them and wanted to keep our yield high and acceptance rate low because we didn't have that many applications to begin with, we'd hold the kids we thought were going to go into Yale and wait for them to withdraw.
I think that's a pretty risky strategy for them to be playing, especially since Yale makes a habit of NOT accepting all of the kids with crazy high numbers, or at least putting them on the WL. Also, I doubt most people accepted to Yale would immediately withdraw from a hold at Harvard, as I would guess many students making the HY decision would want to attend the ASW of both schools. Maybe this strategy could be used for holds, but extending it out past February/March might bring some risks, especially as that student accumulates significant scholarship offers and starts to visit the ASW of other schools. Harvard isn't immune from the #3-5 (aka Stanford, Chicago +Ruby, Columbia +Hamilton, etc).