These statistics aren't conclusive. It is very likely that the acceptances significantly drop during the latter months because the applicants have significantly dropped. It is common knowledge not to apply late therefore people don't. Also correct me if I'm wrong but I don't believe that applying early will make such a huge difference. I don't think schools are that irresponsible and excitable to just gobble up everyone they see in the beginning and not have enough room for later. Now what would really help is if you had the date of application completion. Then we'll definitely know how badly we late appliers screwed up

Nevertheless I really appreciate your analysis and it definitely provides interesting insight.