<p>Huh. That’s weird. Well, I can only say that I submitted my supplement on 9/16 and submitted the Common App (and payment) on 9/22. I got the application acknowledgment from Northeastern on 10/11 and there was no mention of a failure to submit the app/supplement in the correct order and everything on my application status page looks correct. So, I think the typical process on commonapp.org outweighs those instructions. Best of luck with your application!</p>