That is why it is important to get a 24 hr cortisol saliva test done. A lot of the symptoms are the same for high and low cortisol. If you treat high cortisol with isocort, licorice, etc... you are just going to make yourself sicker.
Conversely, as you pointed out, taking phosphatidyl serine when you have low cortisol will only make things worse.
When my adrenal fatigue was at its worst and my cortisol levels were really elevated, I had a lot of the same symptoms that low cortisol causes. I even experienced nausea and low blood sugar.
The problem, I think, is the term "adrenal fatigue". It doesn't just mean low cortisol. Doctors think of Addisons when we mention adrenal fatigue, which of course is severe adrenal insufficiency. On the other end of the extreme spectrum is Cushings. Adrenal fatigue simply isn't the same for everyone and although many on this board are dealing with low cortisol, there are others that are dealing with high cortisol and both are adrenal fatigue.