alien, the credit allowed under subsection (a) shall be treated as a credit allowed under subpart C (and not allowed under this subpart). (2) Increase in applicable percentage Subsection (a)(2) shall be applied— (A) by substituting 50 percent for 35 percent , and (B) by substituting $120,000 for $15,000 . (3) Increase in dollar limit on amount creditable Subsection (c) shall be applied— (A) by substituting $6,000 for $3,000 in paragraph (1) thereof, and (B) by substituting twice the amount in effect under paragraph (1) for $6,000 in paragraph (2) thereof. (4) Inflation adjustment of dollar amounts In the case of any taxable year beginning after 2019, the $120,000 amount in paragraph (2)(B) and the $6,000 amount in paragraph (3)(A) shall each be increased by an amount equal to— (A) such dollar amount, multiplied by (B) the cost-of-living adjustment determined under section 1(f)(3) for the calendar year in which the taxable year begins, determined by substituting 2018 for 2016 in subparagraph (A)(ii) thereof. If any increase determined under this paragraph is not a multiple of $100, such increase shall be rounded to the next lowest multiple of $100. . (b) Conforming amendment Section 1324(b)(2) of title 31, United States Code, is amended by inserting 21 (by reason of subsection (g) thereof), before 25A . (c) Coordination with possession tax systems Section 21(g)(1) of the Internal Revenue Code of 1986 (as added by this section) shall not apply to any person— (1) to whom a credit is allowed against taxes imposed by a possession with a mirror code tax system by reason of the application of section 21 of such Code in such possession for such taxable year