User blog comment:B214/Volume 22 spoilers/@comment-95.90.227.74-20161022133329/@comment-1359322-20161024021043

Or they could make a bigger mess out of it by going all original. In BorN the round robin tournament for the Youth Devil RG got changed to elimination style.

So they change it to Rias vs Sona where Issei unlocks the Triana/something new, then ORC go to Kyoto (1st and 3rd year included), Issei unlocks CCQ/something new. Maybe the RG with Sairaorg if Rias doesn't loses, then the anime ends.