(1) at the same time and in the same manner as under section 415(d) of the Internal Revenue Code of 1986, except that the base period shall be the calendar quarter beginning July 1, 2017, and any increase under this paragraph which is not a multiple of $50 shall be rounded to the next lowest multiple of $50. . (3) Conforming amendment Section 204(d)(1) of such Act ( 29 U.S.C. 1054(d)(1) ) is amended by inserting in effect after the dollar limit . (c) Effective date The amendments made by this section shall apply to plan years beginning after the date of the enactment of this Act.