Beer + Science. The ultimate combo.
Nice experiment, but I have to admit I'm not that surprised. Given the fact that you are chilling the wort while the yeast is reproducing, and that they appeared to be nearly the same temperature at 24 hours, I would have been surprised at dramatic differences between the two batches. It would be really interesting if you let the experimental batch really get going at 75, and then ramp down to more typical ale temps. I would imagine you'd really see a difference then (since I've done it, albeit not controlled or intentional...)
Nice work.