I just started my nutrition log yesterday.  I had a late, unexpected snack and when I went to post to my log late last night I wasn't able to update it.  It was already in a "print-type" mode.   I am on PST.  Does this make a difference?  Does the nutrition log for any given day "close" at a certain time so you can't update it if it's late at night?  Thanks. 

No, it doesn't ever "close." At the bottom of the page there is a calendar that you can use to select any day to edit, including the day that ended a few hours ago.