Section 13. All plans filed for registration under this chapter with twenty-five or more participants shall provide a statutory vested benefit.

Any trust or fund which subsequent to registration has fewer than twenty-five participants shall continue to comply with the provisions of this section. Notwithstanding any provision in any pension plan or profit sharing retirement plan which provides or will provide an annual benefit upon termination of service prior to normal or early retirement date or an interest in the profit sharing retirement plan which is greater than the following, an employee who has been in covered service for a period of ten years, will be entitled, upon termination of service prior to attaining normal or early retirement date (a) in the case of a pension plan, to a deferred pension benefit commencing at his normal retirement date; or (b) in the case of a profit sharing retirement plan, to nonforfeitable right to his interest in such plan, in an amount equal to the lesser of (1) fifty per cent of the accrued portion of the normal retirement benefit as provided by the plan in respect of such service, or of such interest, respectively; such amount to be increased by ten per cent for each year thereafter of covered service until the completion of fifteen years of covered service after which such participant shall be entitled upon termination of service prior to normal or early retirement date equal to one hundred per cent of the accrued portion of the normal retirement benefit as provided by the plan with respect to such service, or to the full amount of such interest in the profit sharing retirement plan, or (2) in the case of a pension plan, a pension equal to fifty per cent of an amount equal to three-fourths of one per cent of annual salary subject to social security tax for each year of covered service, increased by ten per cent for each year thereafter of covered service until the completion of fifteen years of covered service, after which such participant shall be entitled to a deferred pension benefit commencing at his normal retirement date equal to one hundred per cent of such three-fourths per cent of annual salary subject to social security tax for each year of covered service, or in the case of a profit-sharing retirement plan, a pension equal to fifty per cent of an amount equal to three and three-fourths per cent of annual salary subject to social security tax for each year of covered service, increased by ten per cent for each year thereafter of covered service until the completion of fifteen years of covered service, after which such participant shall be entitled to a deferred pension benefit commencing at his normal retirement date equal to one hundred per cent of such three and three-fourths per cent of annual salary subject to social security tax for each year of covered service.

Service by an employee prior to the age of thirty with less than five years' service may be ignored in determining covered service under this section unless such participant has contributed to the plan with respect to such service. In no case shall an employee with more than five years' service regardless of age, or upon an employee's thirtieth birthday be excluded from covered service.

The board shall prescribe standards consistent with the purposes of this chapter governing the maximum number of working hours, days, weeks, months, which shall constitute a year of covered service for purposes of this chapter.

Every pension plan, subject to the provisions of this section, shall provide that contributions will be made to the trust or fund each year commencing January first, nineteen hundred and eighty, or the effective date of the plan in an amount equal to ten per cent of the estimated liability for statutory vested benefits which will accrue during each year of each succeeding ten year period, such ten year period beginning the later of the first year of required contributions or the most recent year in which required annual contributions were made, so that during each succeeding ten year period, contributions will be made to the trust or fund in amounts equal to the liability for statutory vested benefits as such benefits will accrue.

All pension plans subject to the provisions of this section shall provide that special payments shall be made if the pension plan has an experience deficiency with reference to contributions made with respect to statutory vested benefits. Such special payments shall consist of no less than equal annual amounts sufficient to remove such experience deficiency as determined except where the experience deficiency cannot be removed over a five year period without the amounts required to remove such deficiency exceeding the allowable limits for a tax deduction under the provisions of the Internal Revenue Code, for any particular year for which such payments must be made, the board shall, consistent with the purposes of this section, prescribe such additional time as may be necessary to remove such deficiency within allowable tax deductions.