This might not be the most PC thing to admit, but it's possible that PDs are filtering for other demographic data in addition to AOA/step scores/geographic ties/etc. At one of the virtual open houses earlier this summer, a PD explicitly mentioned that they were planning on recruiting more students from URM groups. For example, women traditionally make up a third or a quarter of the applicant pool, but a program may decide to give half of all of their interview slots to women to match a more diverse class.
I'm just bringing this up because I've gotten DR/IR interviews at some uber-reach programs that I didn't expect, especially this early. I feel pretty good about my stats and my app overall, but you know, imposter syndrome and all that