Are we sure 'value2' is the end date ?    If this was sorting by end date, then why an september end date would be before an May end date http://drclas.harvard.edu/ .  I would expect the opposite. 
@rbran100 to answer you question, Peter here http://goo.gl/L7z6c3 is saying that "if someone was a couple minutes late and checked the website with their handheld, the event data was gone".  I agree with him.