(a) A party or support enforcement agency seeking to enforce a support order or an income-withholding order, or both, issued in another state or a foreign support order may send the documents required for registering the order to a support enforcement agency of this State.
     (b) Upon receipt of the documents, the support enforcement agency, without initially seeking to register the order, shall consider and, if appropriate, use any administrative procedure authorized by the law of this State to enforce a support order or an income-withholding order, or both. If the obligor does not contest administrative enforcement, the order need not be registered. If the obligor contests the validity or administrative enforcement of the order, the support enforcement agency shall register the order pursuant to this Act.