There must be a limit to how much testosterone the body can produce out of a specific dose of synthetic testosterone.
Here is an example: If the highest possible level (ng/dL) out of 100 milliliter of synthetic testosterone is 500 ng/dL, then I won't really be able to produce more than 500 ng/dL when I use 100 mg testosterone a week. Whatever level I get from such dose, it will be lower than 500 ng/dL.
If there is data on the highest level of testosterone ever recorded out of a specific dose of synthetic testosterone, I will know the EXACT dose I need.