Strange news about next shuttle flight

Can somebody actually explain this to me: NASA bumps return to flight. The strange thing is that this article claims that they changed the date because they had worries about "lighting conditions". Do they have some type of Egyptian Sun God device to which the light has to align perfectly or else they can't have a launch? It's only 3 days of difference, it's not that the sun will be on a very different position!

Oh, well... NASA people like to do strange calculations for everything! We just hope one team didn't use the English measurements while the other used metric.