Making money online through Adsense and other ad networks

Rohan Pinto is dissatisfied with the three AdSense units that are showing the same ads on his Konkan.tv video sharing site.

Quoting Rohan on his AdSense dilemma:

"I have 3 Adsense blocks on 1 page. Sometimes the same ad is displayed in all 3 blocks and sometimes in 2.

Is there a way for me to setup Adsense such that Adsense throws 3 different ads on the same page in each of the blocks?"

Amit Agarwal of Labnol.blogspot.com  advised Rohan to send an e-mail to AdSense support team about his request and also suggested that he uses different AdSense formats and if it still fails better set an ad as a text only ad and another as an image or text_image ad. Also, the use of the AdSense Preview Tool was given as an added advice.

Have you also observed such situation on your sites? If it bothered you, what steps have you done to solve it?