The amounts transferred pursuant to Section 30682 shall be repaid to the respective accounts from which transferred, but no repayment thereof shall be required until all obligations issued by the commission for the construction of the toll bridge and all bonds issued for refunding of the bonds and for additions, betterments, and extensions to the toll bridge, including new and additional approaches thereto, have been fully redeemed and paid, and then only out of the tolls and revenue received from the operation of the toll bridge.