(2) The total amount of the bond or bonds required of any user of fuel in a motor vehicle shall be fixed by the department and may be increased or reduced by the department at any time subject to the limitations provided in this section. The total amount of the bond or bonds required of any user of fuel in a motor vehicle shall be equivalent to twice the estimated monthly tax of the user, determined in such manner as the department considers proper. However, the total amount of the bond or bonds required of any user of fuel in a motor vehicle shall never be less than $10. Any bond given in connection with ORS 319.510 to 319.880 shall be a continuing instrument and shall cover any and all periods of time including the first and all subsequent periods for which a license may be granted in consequence of the giving of the bond. The liability of the surety on the bond for the aggregate of all claims which arise thereunder shall not exceed the amount of the penalty of the bond. No recovery on any bond or any execution of any new bond shall invalidate any bond, but the total recoveries under any one bond shall not exceed the amount of the bond. [Amended by 1959 c.188 §5; 1967 c.359 §692]