Whenever the losses and expenses in any year shall be less than the amount of the entire premium income of the year, the remainder of the premium income shall be set apart in the reserve fund: Provided, That when the reserve fund shall equal seven thousand five hundred dollars the company may return to the members so much of the premium income in excess of the amount required for losses and expenses as may exceed ten percentum of the total premium income of the year. Whenever the company’s premium income of the year is insufficient to pay the losses and expenses of the year the company shall pay such obligations from the reserve fund. Such part of the reserve fund of the company as is not needed for immediate use of the company shall be invested as provided by section 40-227.