I have noticed that my AD position in google search changes when I am in different browsers, and whether I am logged into google or not. This is not what I paid for. If you pay in the bidding process to be #2, and end up being #4 or less depending on browser or whether logged in, this makes no logical sense. Has anyone else noticed this phenomenon?
Try it yourself. Try different browsers, logged in and not logged in. I have tried it with Firefox, Chrome, and Internet Explorer. My ads are at different positions in each one. And sometimes they are on the top highlighted in yellow, and sometimes over to the right sidebar. Totally inconsistent.