Cool, didn't know that cpc could go as high as that.
I have had click values all over the place from a few cents to 1 buck +, but I think that if you see an arrow on your Ad unit where the visitor can see some more Ads, then I think it means that your page is Smart-priced and you are getting the minimum payments. But, there are various performance optimizations to explore such as accepting image or text Ads rather than just text. And there are various options now that could be used to maybe up the pay rate of your Ads such as screening out certain Ad networks (but there are around 8000 of them to examine).
Maybe by utilizing the latest features of Google Analytics, it may be possible to optimize your Adsense units for maximum revenue? Or you could split-test different Ad unit code.