Repeat of Low-Temperature Mixing Again Yields Bad Results

I repeated the two-minute creaming time experiment and got the same results as this morning. Here are this morning's measurements and this evening's:

Starting Temperature:
68.4 - 68.5

Ending Temperature:
69.1 (change of 0.7) - 68.8 (change of 0.3)

Weight of creamed butter/sugar, not including weight of cup:
197g - 204g

Percent volume increase during creaming:
31.0% - 26.5%

Weight after mixing in the flour, not including cup:
247g - 247g

Percent volume increase during creaming and mixing:
0% - 0%

The weight of one level cup after mixing in the flour was exactly the same this morning and this evening, less than what I measured when I simply mixed melted butter, sugar, and flour. I think I need to use this weight, 247 grams, as representing the weight with no air, rather than the 253 grams I measured with melted butter.

The baked cookies came out the same way again, quite flat, spreading even on the William-Sonoma Goldtouch Commercial Quality Cookie Sheet. There was more pitting on the Wilton pan than I saw this morning, for some reason. The photo of the cookies from the Wilton pan is attached.

These experiments are now using Crystal Farms unsalted butter.

This procedure definitely doesn't make good cookies. The exact same procedure worked much better when I let the butter warm to 75 degrees, and then cooled it back down to 68.9.

I want to get one more creaming measurement with Crystal Farms butter for two minutes' creaming time at this starting temperature. I won't bother to make those cookies - it's clear now how that works out. After the creaming measurement, my next experiment will also be two minutes creaming and two minutes mixing, but I'll raise the starting temperature to 70.5, which would allow an ending temperature for creaming this is around the same temperature of other experiments with two minutes' mixing that worked out well. See my posting from March 14. The only difference between this experiment and the ones reported on March 14 would be the creaming time; the temperature at which flour was added would be the same for those other experiments that worked out OK. If it does work, I'd also be expecting the volume of air remaining in the dough after mixing in flour to then be the same as in the other experiments that work, i.e. somewhat more than 0%!