Old post, old info...
In general cloaking is a war between the service and the ad network(s). IPs are less and less important because all the major networks use shadow bots, partners, and manual reviewers. So having IP ranges is necessary but wholly insufficient. What happens with any of the better services is a back and forth -- we do traffic analysis (manual and automated) to identify new IPs and more importantly fingerprints (patterns of usage), things work for a while, then the networks make a change, add a partner, etc. and eventually we get someone with good settings/practices that gets hit. Back and forth it goes. Ideally this doesn't happen but we don't live in an ideal world and the better services are good because they have support and react to changes.