Adding the clinical framing, because it changes how the question reads. Order of operations matters more than any single choice here: establish a baseline, change one thing, wait long enough for it to express itself, then measure again under the same conditions.

PharmHunterJen said:

Order of operations matters more than any single choice here: establish a baseline, change one thing, wait long enough for it to express itself, then…

This is my experience too, for whatever a second data point is worth. The detail I would add is minor and it is already implied above.

PharmHunterJen said:

Order of operations matters more than any single choice here: establish a baseline, change one thing, wait long enough for it to express itself, then…

There is a second half to this that has not been said yet. The distinction that resolves most of these threads is between what is true on average and what is true for one person. Both are real; they answer different questions and get quoted as if they were the same one.

I would rather be corrected than agreed with, if it comes to it.

The figures, for anyone assembling their own picture. Worth stating the units and the reference range whenever you post a number here. A large fraction of the apparent disagreement in these threads is two people using different units and both being right.

One thing that is still open after PharmHunterJen’s answer:

What did you change at the same time, and can you separate the two now?