When is the close out date? If it is Sept 30th, than this is typical because noms are not rolling. They typically will gather and hold onto the files until they are near their close out date.
One main reason why is that the coordinator at the MOCs office is just that...the coordinator. They do not sit on the board for selection process. Doing a mass mailing to all candidates a week prior insures that paperwork would not be lost in the system if they did every applicant in a piece meal approach.
Frustrating? Yes, but sometimes there is a rhyme to their reason. For them, it is contacting the applicants prior to acknowledge that they are in receipt of all materials, or just partials.