I know what you mean about the about-face the WAS can do with respect to their attitudes. One day its negative and no talking and the next they act like your best friend.
If I were you I would not read into it. WAS can display behaviors that we least expect. They will say and do things to get a reaction out of you. What matters most, I believe, is how you react to her actions and behaviors. Always PMA with the WAS. Even if it hurts. I still have trouble with this but acting AsIf helps over time with getting your emotions under control.
That is where my W is now. After she told our MC that she wants a D, a couple hours later she was acting like the wife I was married to just 5 month ago.
I think that getting that off her chest has allowed her some peace and stress relief. I was admonished by her not to read into her being pleasant towards me as a sign that she is willing to work through our issues, so I wont.
Until I am served papers I will just enjoy our time together and keep working on being the man she would be a fool to leave. We will see what happens.