Ad Mediators - Requests

I read a blog about how ad mediators make requests to multiple providers simultaneously. Is this true? From the article:

"Mediators request ads from all embedded SDKs simultaneously then discard all but the highest paying impression. The problem here is that if an ad is called then ignored, the impression is still counted, and if it’s counted and never shown, it’ll kill your CTR as there’s no way for the user to see and click. Initially you might be thinking: “Great, Adwhirl will artificially increase my impressions and I’ll get more money.” Wrong. It will increase your impressions but it will artificially decrease your CTR. The networks will effectively start ignoring your ad requests; some networks will ban you for fraud. You’ll hurt on ad fill开发者_Go百科, ad quality and CPMs."

I was thinking about using AdWhirl, but if this is the case, I might not (and use my own custom solution). I am bit skeptical because the blog was written by MobClix.

AdWhirl does NOT make requests to multiple providers simultaneously.

Based upon your configuration settings, AdWhirl will randomly select a primary ad network and request an ad. If it cannot get an ad from the primary ad network, it will fallback to the backfill priority, which you can also configure. AdWhirl will request an ad from backfill priority 1, and if that doesn't succeed it will request an ad from backfill priority 2, incrementally until it finds an ad to display.