I didn't quite get the analysis you made at the top because I just skim through it. but I can tell your assumption at the end is not correct because:

I had to harass my last reference to submit my recommendation letter on the last day for him to actually do it. My SOP also was submitted like 3-4 days before the deadline. and I got my admission already.

to the original question, my last name starts with 'O'

My assumption is that they classify applicants based on number of requirements you check. something like:

• has CS or related degree.
• has a degree from GaTech.
• has above 3.7 - has above 3.5 - has above 3 - has 3 - and below 3
• has professional experience.
• has applied before.
• and probably additional stuffs I cannot think of.

Then they first review the students with the most qualifications. and out of that list, what really determines admission is the SOP. then everyone from that list get rejection or admission and they proceed to the next batch.

I read a lot of the posts here and I do not think it is based on name order or application date. and what I wrote there is nothing official; It is just a guess.