GOOD QUESTION!!!

You've seen this issue for decades so here's the deal. The date and time methods are noted in this article.

http://msdn.microsoft.com/en-us/library/windows/desktop/ms724290%28v=vs.85%29.aspx

So there you go. The date/time can change as you use various file systems.

-> Sorta makes you wonder why this was never standardized?
Bob