I am doing the opposite. I took Google's advice and added more ad units to each and every page "as they suggested" --- and started running image based ads on a site "as they suggested".
Previously the site had exactly (1) ad unit per page and no image ads.
The first couple days were pretty dismal -- then the ads seemed to get more targeted and earnings went up.
My other reason for adding the units was to see if the site would recover some lost PR, (not that I think for one minute that Google would ever consider boosting a page just because it had more adwords/adsense ads)...............................