The committee meets every Thursday night, you know that? Some people heard back a few days or about a week after interview (Waitlist, Acceptance, Rejection, etc.)
This is not a proven fact yet: A long wait time usually means the committee needs more time to talk about your application and can't make a decision yet. Alternatively, sometimes adcoms wanna check up on some info on your app (LOR writers, etc.) and that may delay the decision as well.