There are many factors to consider while moving the domain names away to another Provider. I am currently using around 5 PPC Providers, as far as all of them have different models, I am trying to find the one which performs best for the specific domain. It is not easy, when you have large portfolio but worth it. For one of my domains, which was travel related and getting around 800-900 uniques per day, the CPC was $0.12 at TrafficZ and then I moved it to park and it became $0.23. Pretty much difference if we take into consideration that they both use Yahoo feeds. Later on I moved it to DomainSponsor and CPC became around $0.36-$0.4. So try different parking providers and you will find the best one for your domain.