(1) For the purpose of computing pension benefits a member may be paid a full or a reduced pension:

Provided that such a member may exercise the option for a part lump sum payment of twenty-five per centum of his pension and a reduced pension payment.

(2) The minimum pension payment shall be based on fifty per centum of the average annual salary for the three best years of a member during his working life.

(3) Where a member works beyond the minimum contribution period the amount of pension payable shall be increased by one decimal point fifty per centum for each twelve months worked up to a maximum of eighty per centum.

(4) Notwithstanding subsection (2) of this section no pension payment shall exceed eighty per centum of the average of the highest salaries in the top five per centum bracket of contributing members.

(5) Where there are grounds to suspect that the annual salary has been inflated with intent to defraud, the Trust shall have the power to investigate and thereafter the right pension payment shall be made to the member concerned.