We have just transferred from the CSA to CMS this month... the changeover has not been straightforward and I can't work out how they've calculated the yearly amount due plus the 7 weeks that's owe from the end of the CSA schedule. But what has annoyed me the most, is my ex being able to claw back 11% because he lives with another child (not his). This child receives CMS payments from his biological father. Why should my 2 DCs miss out because he chooses to contribute to a child which isn't his? Or am I not understanding this part of the legislation? Can anyone advise?