If I had a densitometer and I was able to control everything else to a very fine degree, I might be able to measure it.
Yes, you can measure it till about 8-10 minutes developing time. So if you're going on consistensy you could make the decision for developing times till 10 minutes with a stop and above without a stop.

When having 4x water change you also need water on the same temperature. Just when using a stop all chemicals should be already on the same temperature. So your process is less complicated too unless you want to run in unwanted reticulation on a certain moment.