Section 17. Whenever it appears by a valuation certified to by a competent actuary that the actual assets of a society exceed its liabilities, including in such liabilities the tabular reserves computed on the basis specified in section 16, by an amount equal to 5 per cent of such reserves, increased by an amount equal to all its other mortuary liabilities, it may, by vote of its officers having the powers of directors, and for such period as its assets are maintained at the levels set forth in this section, waive the further collection of the regular mortuary contributions from its members. A society maintaining a surplus of assets in excess of such amount as enables it to waive contributions under this section may pay to its several members an equitable portion of such surplus in such manner as may be determined by vote of such officers.