U.S.C. 1254a ), the extension under such subparagraph shall be for a period not less than the period for which deferred action or temporary protected status originally was granted by the Secretary of Homeland Security. (b) Immigrant visas (1) Extension of visa expiration Notwithstanding the limitations under section 221(c) of the Immigration and Nationality Act ( 8 U.S.C. 1201(c) ), in the case of any immigrant visa issued to an alien that expires or expired during the period described in subsection (d), the period of validity of the visa is extended until the date that is 90 days after the end of such period. (2) Rollover of unused visas (A) In general For fiscal years 2021 and 2022, the worldwide level of family-sponsored immigrants under subsection (c) of section 201 of the Immigration and Nationality Act ( 8 U.S.C. 1151 ), the worldwide level of employment-based immigrants under subsection (d) of such section, and the worldwide level of diversity immigrants under subsection (e) of such section shall each be increased by the number computed under subparagraph (B) with respect to each of such worldwide levels. (B) Computation of increase For each of the worldwide levels described in subparagraph (A), the number computed under this subparagraph is the difference (if any) between the worldwide level established for the previous fiscal year under the applicable subsection of section 201 of the Immigration and Nationality Act ( 8 U.S.C. 1151 ) and the number of visas that were, during the previous fiscal year, issued and used as the basis for an application for admission into the United States as an immigrant described in the applicable subsection. (C) Clarifications (i) Allocation among preference categories The additional visas made available for fiscal years 2021 and 2022 as a result of the computations made under subparagraphs (A) and (B) shall be proportionally allocated as set forth in subsections (a), (b), and (c) of section 203 of the Immigration and Nationality Act ( 8 U.S.C. 1153 ). (ii) Elimination of