The reason is that even though my testosterone levels are optimised only to the upper ranges of natural physiological levels in males, my testosterone level on TRT does not fluctuate, unlike the body's natural production which will peak and trough through the day.
The adult male naturally produces on average 6-10 mg of testosterone a day and the amount is the highest in the morning and goes down by the end of the day. Testosterone production is also affected by lifestyle factors such as sleep quality, stress levels, nutrition and sexual habits. Some days the testosterone levels of a man will be low, and some other days it becomes higher.
However, for men like me who are on TRT, the exogenous testosterone levels do not fluctuate on a day-to-day basis but follow a wider peak and trough across the 10-week cycle as shown in the graph below.
At the 1-3 weeks mark after the injection of testosterone undecanoate (nebido), my testosterone will peak at the upper level of total testosterone at 800-1000ng/dL. Subsequently, as a result of the elimination half-life of testosterone undecanoate in castor oil, the testosterone levels will deplete up to the 8-10 week mark where it returns to my baseline level of testosterone.
Adding a note, even though I am enhanced/optimised, it is nothing compared to the enhancement that performance-enhancement drugs give, which would bring the hormone levels to supraphysiological levels (way above natural human achievable capacity).