Here's a copy of my fits header for a sub that I was there when it downloaded. This certainly doesn't correspond to an actual time as it isn't even dark here by these times!
Here's a copy from explorer saying at what time this file was ammended - Presumably that means the download time .... this is correct as this is the time that it downloaded and it was my first sub of the night.
Sorry I didn't mean 6 hours difference, as I looked at the minutes and not the hours! So as it stands I am always getting a 2 hour difference between my actual PC time and the time that goes into my fits header.