On application by the owner and approval by the Secretary, the tonnage of spaces prescribed by the Secretary may be excluded in measuring under this section the gross tonnage of a vessel measured under
section 14512 of this title. The spaces prescribed by the Secretary shall be comparable to the spaces that could have been excluded under
[section 2 of the Act of September 29, 1965] (
[Public Law 89–219],
[79 Stat. 891]), as section 2 existed immediately before the enactment of this section.