I don’t know, I assumed it’d be happening during POP but I didn’t verify it because I didn’t see much difference.
As Picolisimo wrote: " If you’re accepted to POP […] it just means that you are already the kind of student they’re looking for." So I would hope the interview is a chance to cement that impression, and that it is a little more than their regular interview. As you know, Pomona completely deflates the relevance of their regular interviews. From their site:
“Since we do not track demonstrated interest, interviewing does not advantage you in the admissions process.”