Judging from the spreadsheet it looks like the 9/7 class had aircraft assignments with the 6/1 drop. This is due to the 9/7 class being almost entirely Compass pilots who were added to the Delta seniority list 6/1 but held back from training for 90 days. It looks like that means they are mostly training for 7ER NYC or 73N NYC/ATL.

We'll find out the 9/21 drop on 9/21 if anyone in that indoc class is kind enough to post. If I had to guess I'd think 7ER is becoming less likely with reducing block hours this Fall.