Years back, I would have sworn that they do them all at once - so no advantage to getting in earlier. Now, it seems to vary from school-to-school. Helped a moderately competitive applicant last year and had everything in by October. Surprisingly, 5/10 acceptances came before TG. Some were rolling and some were EA.
It was a pleasant surprise.
Although I can’t agree with the post, I am afraid the additional applications may have shifted certain schools to get things going earlier.