Do you mean three blood tests or that you did three different types of tests to measure Cortisol (like blood, urine, saliva... or something different)? I'm assuming that you were measuring your Cortisol levels while you were still taking some dosage of Cortef (or had you completely tapered off of it for the blood tests)?
I have never taken Cortef. I find your use of it confusing. I had to look it up the first time and founf out it's brand name hydrocortisone. Most people don't take the brand name, as their insurance will only cover the generic, in this case hydrocortisone. I realize you're lucky as you got a tier exception from your insurance company, just like I did for another brand name drug that I was allergic to all other forms of. But, for readability for most people, hydrocortisone is a more useful word.
I had 2 blood morning cortisols and a 24 hour saliva test over 3 months all suggest my cortisol was high. The 2 morning cortisols were in the higher half of the normal range, and this is what the 24 hour test showed, while taking 5mg hydrocortisone at 1030am and 5mg at 3pm.
This wasn't straightforward, as taking my blood at 9:30am didn't really illustrate the problem, as shown by the graph.
A year later, after slowly dropping my cortisol dose, by using as little as I could get by with, dropping from the 10mg daily in 2 doses to 2.5mg in one dose at 1030am, this is what the curve looked like:
So, this was a little low in the afternoon, so I moved the dose later to 1pm.
This was 2 months prior to the adrenal crisis when I had the added stress of this one time drug, which my adrenals couldn't respond to. So, most of the time, between my own production and the little hydroxycortisone I take, I'm fine. However, I now learned if my body is going to face additional stress, I'm going to need to compensate for my adrenals not rising to the occasion, and supplement extra hydrocortisone.
The other factor I have going on is that I am still doing IVIG every 3 weeks, an example of an extra stressor. For this, my doctor has anticipated my need and given me a stronger, longer acting steroid, SoluMedrol, then the next day, I take a little dexamethasone, followed by a higher dose hydrocortisone day, before tapering down to my normal hydrocortisone dose. This extra burst of steroids for 3 days every 3 weeks probably isn't helping full recovery of my adrenals, and I do have to manage a mix of steroids, but even with all this going on, my adrenals are working to a degree and have vastly improved from where they were in 2016 when I started around hydrocortisone.
The other thing that I do is ensure that I am supporting adrenal function with nutrients that are needed by the adrenals, like vitamin C and pantothenic acid, vitamin B5. And Vital Nutrients Adrenal Support:
https://www.vitalnutrients.net/adrenal-support.html
I'm not sure if this helps my ACTH or not. I believe mine works to some degree, but am not sure how much.
My apologies... Fat fingers. Adrenal Support... see above.