Originally Posted by ChshreCat
A drop in temp after it's started fermenting could cause the yeast to flocculate prematurely, slowing down or stalling fermentation, so you'll want to keep an eye on that.
Agreed. The first few days are when temperature is most critical (while the yeast is multiplying). After two days, the damage is pretty much done, IMO. I would have left it at the higher temperature just to avoid the risk of prematurely stalling fermentation.
My method is to chill the wort to about 5 degrees below their ideal temperature range so that it's cool during the critical period and let it rise to the top of the range to get good attenuation.