I run several niche sites and baring the ones on finance, real estate and home business, others record near about the same rate per click you got there.
you should all try to optimize your ads and not fill your pages with non-performing units and maybe in this way, you won't proc that SmartPricing. It's true tho, the ecpm goes up/down, it's natural. All i'm saying is that we can do some changes to lift it up a bit