Such a misconception about Seriphos (PS) and it lowering cortisol.
It has an action which reduces cortisol excretion by mitigating the glutamate receptors in the brain, therefore in turn conditioning the Hypothalamus and Pituitary to stop sending signals to the Adrenals for hormones...in essence therefore nuetralising the 'stress' response. It dosent directly 'reduce' cortisol.
So where as it can help the 'stuck in fight or flight' mode, there isn't a time period for this, and it needs to be combined with other therapy, nutritional, mental and physical to essentially 're-wire' the HPA system permanently.
Dosage can vary from one person the next. I have spoke to people that needed over 14 a day (I did last summer after a benzo detox) but now I can only manage 1 or 2. So getting your dosage right is key , and the length of time , is again a process. I know one fella that was on it for nine months, off for a month, then another nine before he had permanent adjustments, but I remember Laredo on here found combining it with ACE, saw an improvement for her in three months.
If glutamate is your problem, I also suggest NAC.
It might be that your cortisol is high for another reason other than a HPA malfunction, could be an underlying infection or something of the like?
If your test shows a permanent high cortisol, think about what could be causing it, and also look at adaptagens like Holy Basil for lowering it, maybe combined with the Seriphos...and definitely C and B5. Maybe even Adrencalm cream?