The security required under this chapter shall be in such form and in such amount as the director may require but in no case in excess of the limits specified in Section 32-7-6 in reference to the acceptable limits of a policy or bond. The person depositing security shall specify in writing the person or persons on whose behalf the deposit is made and, at any time while such deposit is in the custody of the director or State Treasurer, the person depositing it may, in writing, amend the specifications of the person or persons on whose behalf the deposit is made to include an additional person or persons; provided, that a single deposit of security shall be applicable only on behalf of persons required to furnish security because of the same accident.

The director may reduce the amount of security ordered in any case within six months after the date of the accident if, in his or her judgment, the amount ordered is excessive. In case the security originally ordered has been deposited, the excess deposited over the reduced amount ordered shall be returned to the depositor or his or her personal representative forthwith, notwithstanding the provisions of Section 32-7-11.