I also believe that you should keep the faith. You do not know the inner workings, for example, maybe last week M-W, they worked on updating the files for the USMA, T-F for USNA, M-W of this week for USCGA and T-F for USAFA. If they had 70 applicants, it is not as if they contact the 10 that they nominate and throw the other 60 in the circular filing cabinet. They notify each list and create files for them. Typically, it is a staff, but you are not speaking about 20 people, but a few that are less than the amount of fingers you have. The MOCs must also keep their own records, but at the Pentagon there is an office for each branch dedicated to each SA. Now add into this that this same office has to work with the SA admissions office. So as you can see, there is alot of paperwork that goes with each candidate, or in other words man hours.
KEEP THE FAITH until you know for a fact that you didn't get one.
2 yrs ago there was a poster on here who applied for the AFA from our state, he interviewed the same date as our DS. He received the "at this time" letter 2 days before our DS. We received the "congrats" letter. You do not know how the inner office works.