Starting from October 2016 we now only guarantee that only up to three ad units per page will be served to the visitors of your website and here's why.
Unlike other advertising networks, A-Ads doesn't pay merely for impressions or for clicks: we consider globally unique impressions within our entire network. As a result you may realize that having more than several ad units per page doesn't make a lot of sense from the financial point of view: additional ad units might not necessarily bring your additional earnings.
Secondly, we've had many publishers who placed literally dozens of dozens of ad units per page in a hope that extra ad units would proportionally increase their earnings and of course that hadn't helped their cause. Consequently our servers bore a very substantial computational burden and it jeopardized our operations.