All expenses necessary in connection with the administration and operation of the deferred compensation plan authorized in section 84-1504 shall be paid from the Deferred Compensation Expense Fund which is hereby created. The fund shall be credited with the proportionate share of administration expenses from the deferred compensation plan assets and income as directed by the Public Employees Retirement Board for the proper administration of the plan. Any money in the fund available for investment shall be invested by the state investment officer pursuant to the Nebraska Capital Expansion Act and the Nebraska State Funds Investment Act.