Don't have the book with me right now; I am at work.
Mine was off by an hour when I got mine, and I went into the menu of the Nav. sys., and all I had to do was to select the time zone that I am in, it may also have a selection for automatic Daylight Savings time too.
Hope that this helps.
I had the same problem after selecting the GPS block, time zone, daylight savings choice, and then pressing the enter button. I forgot to select the "DONE" block at the bottom of the screen before pressing "ENTER."