Using Adsense with a third party ad rotator

[MrWonton]

An ad retargeting network has approached me about one of my high traffic sites. They want to buy a proportion of my impressions. I only have one adsense ad block on this specific site.

They want to provide me with a baseline minimum RPM (eCPM) higher than what the site currently earns with Adsense. The network will only display their ad when a visitor on my website has a cookie on their computer from one of the network's advertisers (ie, a small portion of the traffic which hits my site).

To make this work, I put the adsense code in their interface, and then use their script to rotate the ads. Most of the time the adsense ad will be displayed, but if the user has a cookie from one of their advertisers, then the retargeted ad is displayed.

The company looks extremely legitimate, with very large advertisers, etc.

I am confident that I can increase my earnings, although I'm not sure how sensitive Adsense is to this type of setup? Does anyone know G's stance on ad rotators, and not actually displaying the script on the site itself?

Please no best guesses/DP answers. If anyone is running a similar setup, I'd love to hear from you.

Thanks