Interesting AdSense Finding

This is a somewhat interesting, and also disappointing, thing to find out about the Google AdSense program. I can't say my finding would hold true for everyone, or is actually a fact in their systems or perhaps just dumb luck for me.

A few months back I switched from using the standard AdSense system to manage my ad spaces to using the Google Ad Manager. The Ad Manager allows AdSense to be used as backfill for spaces that don't have other inventory to fill the spaces with. By and large I used it exclusively for Adsense anyway, and rarely used it for privately bought ads.

About that time ad revenue started falling with the economy in general, I really didn't think much of it. However, with revenue still dropping I decided to try something. Since the bulk of my spaces I kept as only AdSense I went back to the AdSense standard control panel to just have permanent AdSense code in my pages.

After doing that I found my revenue to start climbing again. Is there a connection there? I don't know, but, if you use Ad Manager Google does know, via the application, how much any privately sold ads are selling for, and could, presumably, manipulate the revenue or bidding process accordingly I suppose, if I were a conspiracist type of thinker...which I am...

I'd be curious if any other people have went back and forth like this and found similar results.