my son's experience:
He applied the first day of opening for each.
USAFA- a girl in DS class found out the next day she got in, DS found out three wks later he did not.
USMA- he found out within a couple days he got in. (DS went and loved it!)
USNA- acceptances seemed to go out in three rounds. A different girl in DS class found out in the first round that she got in. DS found out in the second round (~2 wks later) that he got in. (DS went and LOVED it!!!!!!!!!!!) (On a side note DS got LOA- the girl who got in earlier to NASS did not get an LOA)
A boy in DS group did not get in but then got a phone call a couple of days before the start of session 3 to attend. He lives close by though. He got an LOA.