I went to look at the stats again. The ad I’m having issues with was the very first ad I put up and is the first row below. The 2nd and 3rd ads were put up 1 month later in the same group with a 4×1 grid and are the 2nd and 3rd rows below. All 3 ads are shown 100% every time the home page is shown. The clicks are one thing, but the Shown stat clearly shows the ad got reset when I moved it from the one group to the other.