The time discrepancies on the early tweets, was due to the fact that I had just joined twitter and was not aware that I had to change times zones from the default, which I later corrected.
But yesterday, and today I went to Witherspoon's Twitter feed through gateways other than a link you'd supplied, and the time-zone discrepancy was still there, buried within the Twitter feed.
I don't think it's your fault, but more like Witherspoon didn't change the defaults on his end of things either?
I just went and checked, and Witherspoon's feed is apparently running on Pacific Time.
Mystery solved.
What I don't get (but am not kicking about) is how can Witherspoon be Tweeting from within a courtroom - if cellphones and tablets had been prohibited?