My impression based upon my personal observations as an Area Coordinator for twelve years is that Admissions has a tendency to wait until all the nominating sources have filed their slates before getting to deep into announcing offers. Part of the problem is the matter of candidates with multiple noms. The SA's want to get as many highly qualified candidates as possible and candidates with multiple nominations present the opportunity to optimize their take in this regard.
Locally, I know that most of the local candidates were notified of their noms several weeks before they all were posted on the summary, and it was at least a week after that before offers started to flow... to those with LOA's first, of course.
I hope this helps, and best wishes.