In response the the never ending "make ads more visible" guidance from the AdSense team I tried it on about 100 pages. I replaced a 300x250 ad below the main content with a 160x600 to the left of the main content. So now the ad and the main content start at the same distance down the page from the top, and the ad block and the content end at about the same point on the page also in most cases. The result has been about a 50% drop in earnings from those pages. I'm going to reload the old style pages again.
Have you tried putting an ad near the top? Supposedly, if you put an ad near the top of a page, say, just below the title, the Click Through Rate on that ad increases. (Haven't tried it myself to confirm.)
LOL! Its not necessary that Google will always tell you the right thing So I also Suggest to go back to your previous style or try something new. thanks
Your using different type of ads (size) then you did before? This might explain your drop since the amount of advertisers isn't the same on each ad type.