First thing they're gonna do is screen by Step scores. If you make the cut then they start looking at individual apps. Because a committee selects interview applicants, there's a strong possibility that not every committee member is familiar with all the invited applicants. So the chance that they're comparing individual applicants from individual schools is probably small. You should compare yourself to the applicant pool in general and look at previous years' match data to understand how competitive you are.
As an aside, I was invited to interview at top programs that other folks from my school were not invited to, despite having better stats than me. And I was passed over by several schools that invited classmates with lower stats. So to a certain degree, it's a clusterf*ck to try to figure out how interviewees are selected..