Sophomore quota

Those specifics are irrelevant. Well over 150 get a bid each year, and what houses they have gone to in the past depended entirely on how those individual girls fit with certain sororities. If someone comments that they had 12 in their class and someone else had 2, it doesn't mean that those sororities always take those numbers, or explain why they took the ones they did and not others. Chapters don't always take the full upperclassmen quota, upperclassmen rush always goes better for girls who know sorority members, and the reason someone is rushing as a soph kind of matters too.