Our shopping clicks flat-linned -- turned out it was due to a change made to our account by our Google Rep!
PLAs currently **do not work** with their Conversion Optimizer setup -- so you'll want to be sure you are not doing that. When I e-mailed about the situation I was typed to as though I should have known better (Why didn't our Google rep know better?). I made the mistake of trusting our rep!
When I pointed out that our Google rep made the change -- not us -- that comment was ignored in lieu of offering screen shots showing the account was working again. Duh! I knew that -- I reverted the changes myself.
Our rep did call and profusely apologized for his lack of knowledge... But that doesn't make up for the sales lost.