Nothing in this subtitle shall be interpreted as superseding the provisions of section
635a–3 of title
12, except that in the event of an assessment of duty based on a derogation under section
1671e of this title or action under section
1671b
(d)(1)(B) of this title, 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
12.