Software developer/database engineer here. The timestamp thing is a great way to lose your mind trying to make sense out of something that most likely is not related to 'rank order'. It could be based off of the order in which OMSAS accounts were made, alphabetical by name, the date applications were initially received, the last time you logged in to your account, or a million other things. Typically, database indexes are ordered by some sort of date, so created_at or updated_at for the database record. The program would then roll through the records in that order whenever it needs to execute batch actions. Try not to make yourself mad! Go read a book or do something fun instead haha.
I'm on 4 waitlists myself, so I understand the frustration and desire to know what the hell is going on with your future. If you examine the situation from a different lens though, it's actually a bit relaxing. People keep wanting to make plans with me for the fall/winter and my response has been, "Can't do it. I have no idea what's happening with my life." Use this as an opportunity to live in the moment and just enjoy the things around you. In a bizarre way it's a wonderful chance to not worry about the future, as ironic as that is. Good luck everyone!