Update:
I found this by Bill Roberts:
"To understand inhibition of testosterone production, we need to know first how it is produced and how production is controlled. The broad general picture is that the hypothalamus receives a variety of inputs, for example, levels of various hormones, and decides whether or not more sex hormones should be produced. If the inputs are high, for example, high estrogen or high androgen or both, then it decides that little or no sex hormones should now be produced, but if all inputs are low, then it may decide that more sex hormones should be produced. It seems that the hypothalamus doesn’t respond only to current hormone levels, but also to the past history of hormone levels."
The last sentence is the part I am interested in. But still shady. Maybe the blood levels do not have to reach "normal" levels. maybe they just have to reach a level significantly lower than previous levels to stimulate the hypothalamus.
I have realized that there is not a consensus when it comes to clomid therapy. During my research on this topic I have found a few sources which still say just to start when the cycle ends.