There is a lot of bad gouge on this website. I get it. This is probably the only source of "insider info" you can get. As I was an Officer recruiter who recruited all types of designators SWO, NFO, SUPPLY etc. so i know a lil bit more than most. You are right on one thing about age portion and that's called "return on investment", but i would counter with this there are many one tour wonders for non AD personnel who will simply get out to try another careers. The AD quota is tiny so disrupting is simply not true. Most AD guys stay in if selected trust me I believe most AD guys on this forum could agree. Its the civilians who have the time on their side to try at other careers. I am always positive and never give up on your goals. I can say for everyone hurry with these results so we can make our next moves. Good Luck
The officer progression is not designed for a majority to stay in, the who organizational structure is based on those who do one tour and get out, officer retention is pushed by Dept Heads as it makes them look good, but I have had a Dept Head who was pushing his JO's to talk to the detailer and stay and the detailer told them stay or go, we have met our retention quota for your YG, so it can be interesting.
In general most of those who are AD and pick up officer stay until retirement, but there are issues with those with AD time. I have seen quite a few who were picked up with less than 4 years AD who did one tour and left as they didn't have much time invested. Those with around 10 years are most likely going to stay but a lot retire after hitting 20 and that is around the LT/LCDR point, that creates manning issues, and that is the reason why they now limit AD time. It has much more of a negative effect on smaller designators, Supply and IWC used to pick fairly large percentages (compared to other designators) of AD until some of these issues were coming up.