year of participation
(4) (A) For purposes of determining an employee’s accrued benefit, the term “year of participation” means a period of service (beginning at the earliest date on which the employee is a participant in the plan and which is included in a period of service required to be taken into account under section 1052(b) of this title , determined without regard to section 1052(b)(5) of this title ) as determined under regulations prescribed by the Secretary which provide for the calculation of such period on any reasonable and consistent basis. (B) For purposes of this paragraph, except as provided in subparagraph (C), in the case of any employee whose customary employment is less than full time, the calculation of such employee’s service on any basis which provides less than a ratable portion of the accrued benefit to which he would be entitled under the plan if his customary employment were full time shall not be treated as made on a reasonable and consistent basis. (C) For purposes of this paragraph, in the case of any employee whose service is less than 1,000 hours during any calendar year, plan year or other 12-consecutive-month period designated by the plan (and not prohibited under regulations prescribed by the Secretary) the calculation of his period of service shall not be treated as not made on a reasonable and consistent basis merely because such service is not taken into account. (D) In the case of any seasonal industry where the customary period of employment is less than 1,000 hours during a calendar year, the term “year of participation” shall be such period as determined under regulations prescribed by the Secretary. (E) For purposes of this subsection in the case of any maritime industry, 125 days of service shall be treated as a year of participation. The Secretary may prescribe regulations to carry out the purposes of this subparagraph.