4.__Application of law of state issuing controlling order. After a tribunal of this or another state determines which order is the controlling order and issues an order consolidating arrears, if any, a tribunal of this State shall prospectively apply the law of the state issuing the controlling order, including its law on interest on arrears, on current and future support and on consolidated arrears.

Uniform Comment

(This is Section 604 of the Uniform Act.)

This section identifies situations in which local law is inapplicable. A basic principle of UIFSA is that throughout the process the controlling order remains the order of the issuing State, and that responding States only assist in the enforcement of that order. Absent a loss of continuing, exclusive jurisdiction and a subsequent modification of the order, the order never becomes an "order of the responding State." Ultimate responsibility for enforcement and final resolution of the obligor's compliance with all aspects of the support order belongs to the issuing State. Thus, calculation of whether the obligor has fully complied with the payment of current support, arrears, and interest on arrears is the duty of the issuing State. For example, under Subsection (a) the responding State must recognize and enforce an order of the issuing State for the support of a child until age 21, notwithstanding the fact that the duty of support of a child ends at age 18 under the law of the responding State, see Robdau v. Commonwealth, Virginia Dept. Social Serv., 543 S.E.2d 602 (Va. App. 2001); State ex rel. Harnes v. Lawrence, 538 S.E.2d 223 (N.C. App. 2000). Similarly, the law of the issuing State governs whether a payment made for the benefit of a child, such as a Social Security benefit for a child of a disabled obligor, should be credited against the obligor's child support obligation. The amendments of 2001 to Subsection (a) are intended to clarify the range of subjects that are governed by the choice of law rules established in this section.

Subsection (b) contains another choice of law provision that may diverge from local law. In situations in which the statutes of limitation differ from State to State, the statute with the longer term is to be applied. Attorney General v. Litten, 999 S.W.2d 74 (Tex. App. 1999). In interstate cases, arrearages often will have accumulated over a considerable period of time before enforcement is perfected. The rationale for this exception to the general rule is that the obligor should not gain an undue benefit