Harb. & Nav. Code, § 1166

(a) The benefits actually paid out each month by the fiduciary agent or agents designated by the board to all retired and disabled pilots and inland pilots, to surviving spouses of deceased pilots and inland pilots, and to successors in interest shall be equal to the revenue received pursuant to Section 1165 during the preceding month less the expenses of the fiduciary agent or agents incurred during that month. The revenue, whether greater or less than the amount used in determining the tonnage rates under this chapter to provide the aggregate target pensions to which those persons are entitled according to Section 1163, shall be paid to each of them in proportion to the relative target amounts to which they are entitled, after payment of the expenses of the fiduciary agent or agents.

(b) Revenues for any month or year are the amounts to be received pursuant to the pension plan for pilotage during that month or year. The fiduciary agent or agents shall determine which accounting system shall be used to make the payment, provided that, if the accrual method is used, it shall be subject to later equitable adjustments for unpaid receivables.

(c) Benefits pursuant to the new rate calculations shall be paid commencing in February, May, August, and November of each year and shall continue through, and include, the next following April, July, October, and January, respectively, so that each benefit pension period equals three months of payments. The period during which benefits are paid is the benefit payment period.