The administration of the Child Support Agency is the matter for the chief executive. He will write to the hon. Member with the information requested.
Letter from Jos Joures, dated 17 May 2007:
In reply to your recent Parliamentary Question about the Child Support Agency, the Secretary of State promised a substantive reply from the Chief Executive. As he is out of the country I am responding, with his authority, on his behalf.
You asked the Secretary of State for Work and Pensions, what the procedure is for collection of debt by the Child Support Agency for old rules cases where changes in circumstances have subsequently occurred; and if he will make a statement. 
The procedure for the collection of debt is the same for old scheme and new scheme cases. If a change of circumstances, which results in an alteration to the debt balance of a case, is processed the Agency will recalculate the debt balance and contact the non-resident parent to negotiate a new payment arrangement. Under the Operational Improvement Plan, the Agency aim where possible to recoup any outstanding arrears within two yeas, once a payment schedule has been established. However, the Collections and Enforcement Regulations, 1992 prevent the Agency from taking more than 40% of a non-resident parent’s net income in child maintenance payments, and all arrears agreements reflect this requirement.
I hope you find this answer helpful.