Nothing in this subtitle shall be interpreted as superseding the provisions of , except that in the event of an assessment of duty based on a derogation under or action under , the Secretary of the Treasury shall not authorize the Bank to provide guarantees, insurance and credits to competing United States sellers pursuant to .section 635a–3 of title 12section 1671e of this titlesection 1671b(d)(1)(B) of this titlesection 635a–3 of title 12