Treat the interview not as an end-of-probation interview as much as a
pre-command interview. That's how CX will treat it.
It may be 15 years before you get up-graded again, but there are not going to be many logged interviews with you on their file.
As Yeager said (although he may not have meant it!)
Its a great opportunity for you to rock up in full suit
Yes, it is: show them you are a potential commander.