I have a buddy that I went to Junior High/High School with who graduated from the Academy in 04 and was an SNA. He got an 84 on his NAV test in API and they gave him the option of changing communities or running with his free education. He got out and got into real estate and did really well for himself down in San Diego.
Fast forward to now and he is eating ramen noodles and sleeping under a bridge. I hope for his sake that he got out of San Diego real estate at the right time. All my buds who own (and now are landlords) houses there are around $50K in the hole.
It is all based on the current needs of the Navy. If they have holes for the bodies, then they are retained. If not, they are let go. It wouldn't make sense to flood these communities with extra bodies who are not needed or desired. The education costs are sunk, the Navy is not getting them back, but payroll and benefits cost good taxpayer dollars that could be spent on something else. When I first got here, everyone was out of the Navy, it didn't matter what the commissioning source. Now, most are redesignating as long as they are recommended for it. People with OLQ issues or crappy attitudes are given walking papers.
As far as advanced attrites/DORs go, I don't know. Jet attrites used to be sent to other communities if they were attrited in later phases of training, I don't know if that is still the case. Everyone else was generally redesignated. I don't deal with that end of the pipeline, so I just don't know.