I was experimenting to solve a problem. Part of an object kept rising off the bed and making the final print rough and misshaped... I rotated it 90 degrees and that fixed it. What I think now, after lots of suggestions from other forums, is that the fan is more effective from certain angles at cooling the different parts of the object based on position - and in the new position, the vulnerable section was better cooled.
I have a video and lots of images on this blog post: http://goo.gl/C7WDNF