@Publisher - It isn’t a matter of how many cross-admits Williams loses to one individual school, if there are only two cross-admits between them. It’s a matter of which schools the bulk of the cross-admits are with. Thus, if Williams has a total of 100 cross-admits with (let’s say) 9 universities but, 50 of them are with HYP - that is more significant than the two that may have been lost to Columbia or Penn.
TBH, whenever someone mentions, Parchment or Niche, I’m always reminded of that Lyndon Johnson admonition to some hapless political neophyte running for office, “Son, first thing you do is buy yourself a poll.”