The grads are given an option to pay for Tri-Care on their own, or you can pay for them under the young adults because as stated they are not considered Active. At least that was what DS was offered in 12. They should be telling the cadets about that now. I don't recall which Tri-Care package it was they can get. DS opted not to carry insurance because he had a full time job lined up before he graduated for the time he was going to be home, and used the employers healthcare.
Actually time in service does start the minute they commission. Time in rank does not start until they report. It is a little loophole for ROTC, or at least the AF,
For example:
Bullet and our DS commissioned May 25th (25 years apart). Bullet got his longevity pay increase every May. He did not report until March, so the AF took the avg between those two dates and his date of rank was October.
When Bullet retired in Aug 08, he retired with 21 years, although he only had 20 in ADAF time. I don't know about doing four and the door if that is the same....I doubt it, and even if it did, the fact is it is hard to sync up walking out exactly the four year point because of the wait, than the schools they maybe required to attend, and most assignments stateside are 3.4 years. Take TA and you owe more time.
Our DS has the same thing right now. His DOR will be Aug because DS reported earlier. So IOTWs on May 25th this year he will get his two year pay increase, he will pin on his O2 rank Aug 1st. Every promotion board he meets while AD will be based on the Aug 1st date.
~~~~ For those going rated, there will be a third date regarding pay. Flight pay. That starts when you start UPT/UNT/ABM/RPA. DS was on casual at LAFB starting Sept 30th, but he didn't start UPT until April 2nd. His longetivity flight pay is tied to the April date.