Optimal AM Cortisol Levels

What is an optimal AM Cortisol. I had these labs drawn at 10AM. The normal Quest range is noted, but it is not always optimal. I am currently not taking any TRT or supplements but considering DHEA and Pregnenolone as both have previously tested low. My DHEA level is at the bottom of the Quest reference range. I suffer from severe fatigue especially in early mornings. Any information is appreciated

CORTISOL,TOTAL, LC/MS|
Your Value 8.2 mcg/dL
Standard Range mcg/dL
Adult Reference Ranges for Cortisol, Total:

Males and Females
8-10 AM 4.6-20.6 mcg/dL
4-6 PM 1.8-13.6 mcg/dL

CORTISOL,FREE,LC/MS,S|
Your Value 0.22 mcg/dL

Standard Range mcg/dL
Adult Reference Ranges for Cortisol, MS, Free:

8:00 - 10:00 AM 0.07-0.93 mcg/dL
4:00 - 6:00 PM 0.04-0.45 mcg/dL
10:00 - 11:00 PM 0.04-0.35 mcg/dL

If I take DHEA should I take it before bed with lower AM Cortisol levels since DHEA lowers Cortisol?