Sigh... The point is is that some schools have not even started looking through applications/issuing interviews, like I said earlier. We are still in August. We are still at the beginning stages and yes, the order does really matter lol. For example, on my list of 11 schools, only 3 have sent out invites. All the invites have been sent out to applicants who completed their applications/supplement before me and it looks like they're being sent out in order of app/supp completion.
You're talking about further down the road in the cycle. Not today, like your initial post stated. If your stats and extracurriculars are below average (in the eyes of the d-school) and you see someone get an interview who completed their application a month after you, then yes, you are at a disadvantage. You are technically thrown into a pool with all the other below average applicants and then it becomes survival of the fittest.