Section 509A.5 - Fund under control of governing body - interest earnings of certain funds1. The fund for each plan shall be under the control and shall be expended under the directions of the governing body and shall be used solely for the purpose of administering and carrying out the provisions of the plan adopted by the governing body.2. Any interest earnings from investments or time deposits of the funds under the control of the department of administrative services shall be deposited to the credit of these funds.