mememax - 3:40 pm on Dec 6, 2011 (gmt 0)
* Google may see it as an attempt at optimization.
I think this is one issue. Google finds a new title, so it "thinks": -hey something new has happened to this page, let's see what. Then when it enters the page it finds nothing new, so you've changed title to rank better. SERP manipulation attempt --> down in rankings. (at least is what I'll think)
* Short-term losses are to be expected from changing titles.
More than that: "short-term CHANGES are to be expected from PAGE ALTERATIONS".
You got a score, your result is balanced in its position, when you change something this will change something of your "rank". It maybe let you raise or fall but in the short period you mustn't judge as good/bad your changes.