"Bureau for child support enforcement" means the agency created under the provisions of article eighteen of this chapter, or any public or private entity or agency contracting to provide a service. The "Bureau for Child Support enforcement" is that agency intended by the Legislature to be the single and separate organizational unit of state government administering programs of child and spousal support enforcement and meeting the staffing and organizational requirements of the secretary of the federal department of health and human services. A reference in this chapter and elsewhere in this code to the "child advocate office" or the child support enforcement division shall be interpreted to refer to the Bureau for Child Support enforcement.