Someone correct me if I'm wrong please, but looking at the dates/times on TM's posts for the night Heather disappeared, it doesn't look like Tammy has proven she was posting on FB at the "right" times anyway, even if she did change stuff, unless we believe her about DST. I DO think she changed some stuff because some comments from her friends appear before the timestamp on the posts (in at least one instance), but I'm still not seeing how this proves what she thinks it does. I'm also confused at this point what the jury has actually seen of her Facebook.
One thing is CLEAR from this case. Facebook is no alibi.