does adcom read your entire app before offering interview?

Depends on the school. Some it goes through at least two readers before they send out invites. Others its only one reader then you are invited. I think every school has a read after the interview too but its possible there are some that dont do full reads. There are also schools like Kellogg that interview everyone no matter what (as long as they have interviewers in your area)...these they may or may not have gotten to your application before your interview, which are blind anyways and a lot are done by alums. Its possible that at a lower ranked school someone applying with incredible stats coudl be invited very quickly based on those alone.

Basically, there is no answer to your question...it varies by school. As for the schools you got invited from, I know nothing about their app process and how their interview selection works. It doesnt really matter though since almost every school uses blind interviews. Only a few like MIT actually have adcoms interview people after they read the essays.