By ADSO, I'm guessing you mean your ETS date. I think there's a space for it on your ORB. On mine, that space is blank. My ETS is listed on my LES, but I think it's inaccurate. Some people have it on their contract. If you're separating after your initial ADSO, then that'd be the one you signed as an MS4, assuming your's was a continuous one. You can also contact your career manager, because I think they're the ones who will ultimately be responsible for cutting your separation orders.
Get in touch with the S1/Human Resources section at your local MTF. They should be able to go into MODS to look up your AD Obligation Worksheet which will document your training obligation time and your ADSO end date.