Fordham has a funny dynamic as regards BTL’s, because it is the best school in NY which is not Columbia or NYU. Since many frum guys don’t want to leave NY, you have many people there who just missed Columbia/NYU, and are well overqualified for Fordham.
I still have no way of explaining their data, but I think I’d have also been surprised if the data had mapped the rest of the students.
Meanwhile, I really want to see this study. They should totally release it to the yeshivish chevra.