The day after my son received his LOA, the ALO/BGO came to our house to interview him. The interiewer told us he really did not need the interview because he had an LOA. He asked if we had wquestions so we sat down with him. One of the things we brought up was the Nomination from MOC. We were concerned if there would be a problem with that. He told us that LOA was his ticket in. Even if he did not get a MOC Nom, the academy would find him a nominating source ie. Sec of Air Force. My son got his nom from our Senator, so we never had to go to alternative sources.
That ALO/BGO pretty much assured us that the LOA was his in, he pretty much assured us that he would have no worries from that point on. This all occurred on Oct 8 2009. I don't know if things have changed or if the information he gave us is correct.