(a) shall be applied by substituting $3,000 ($3,600 in the case of a qualifying child who has not attained age 6 as of the close of the calendar year in which the taxable year of the taxpayer begins) for $1,000 . (3) 17-year-olds eligible for treatment as qualifying children This section shall be applied— (A) by substituting age 18 for age 17 in subsection (c)(1), and (B) by substituting described in subsection (c) (determined after the application of subsection (i)(3)(A)) for described in subsection (c) in subsection (h)(4)(A). . (b) Advance payment of credit (1) In general Chapter 77 of such Code is amended by inserting after section 7527 the following new section: 7527A. Advance payment of child tax credit (a) In general As soon as practicable after the date of the enactment of this Act, the Secretary shall establish a program for making advance payments of the credit allowed under subsection (a) of section 24 on a monthly basis (determined without regard to subsection (i)(4)) of such section), or as frequently as the Secretary determines to be administratively feasible, to taxpayers determined to be eligible for advance payment of such credit. (b) Limitation (1) In general The Secretary may make payments under subsection (a) only to the extent that the total amount of such payments made to any taxpayer during the taxable year does not exceed an amount equal to the excess, if any, of— (A) subject to paragraph (2), the amount determined under subsection (a) of section 24 with respect to such taxpayer (determined without regard to subsection (i)(4)) of such section) for such taxable year, over (B) the estimated tax imposed by subtitle A, as reduced by the credits allowable under subparts A and C (other than section 24) of such part IV, with respect to such taxpayer for such taxable year, as determined in such manner as the Secretary deems appropriate. (2) Application of threshold amount limitation The program described in subsection (a) shall make reasonable efforts to apply the limitation of section 24(b) with