It is certainly an interesting experiment. Personally, I am in the camp that mingle time doesn't have that big of a difference. However, what I believe has a huge difference is oxidation time. From what I am reading about your experiment, you are not only measuring mingle time, but also oxidation time, especially if the sample bottles had a fair proportion of air in them. To really isolate the effect of mingle time, you would need to also ensure each sample had the same amount of oxidation time, which would mean you have to pull the later samples at the same time as the first test, but only mix at the designated time.
I will tell you what though, I appreciate the time spent on experimenting on this stuff. These things really can affect the way a whiskey tastes at various times.