There is not really an answer for that.
I can tell that you that you have not had enough testing.
When I first started on this ride, I had some test results like yours. People on lots of boards kept telling me it was adrenal fatigue and to take hydro. I wasn't 100% sure of that though and my symptoms did not really match up. Many docs said it was all nothing. Finally, I went to a specialist, who suggested cyclic cushings. Meaning= I can go from high cortisol levels to low cortisol levels in a short span of time. This has really made sense to me. It matches how my symptoms are. I generally have low cortisol in the morning and high at night.
The 2 drs I have most respect for in this arena are testing with saliva, blood and 24 hr urinary free cortisols. Some people have full blown cushings and not all of these tests will come back abnormal.. It is really a personalized thing. Ocne you have a certain amount of documented high cortisols they will usually do other testing to confirm.
If testing for addisons, from what I gather the gold standard test is the ACTH Stimulation test. They should also test your renin, aldosterone and electrolytes.
Everyone is absolutely different, allthough your average endo will not agree...
I hope that I anwered some of your questions.