I've used Ad Agency on other sites and when new ads rotate into the zone, the length of the zone changes when the ad changes so that there is no white space in the zone. On this site, though, when they rotate in, if a longer ad rotates in before a shorter ad, the zone remains the same length as the longer ad, leaving a lot of white space with the shorter ad.
You can see it here. Just watch the ads rotate and you will see the issue.
http://pcpcdev.com/index.php/sports