Thereupon the county commission shall appoint three viewers, possessing the qualifications of viewers appointed under section 243.050 to make such readjustment of assessments in the manner provided in section 243.050 and the viewers shall make their report, and the same proceedings shall be had thereon, as nearly as may be, as are herein provided for the assessment of benefits accruing for original construction; provided, that in making the readjustment of the assessment of benefits, the viewers shall not be limited to the aggregate amount of the original or any readjustment of the assessment of benefits and may assess the amount of benefits that will accrue from carrying out and putting into effect any supplemental plan for reclamation. After the making of such readjustment, the limitation of twenty percent of the annual maintenance tax which may be levied shall apply to the amount of benefits as readjusted, and the limitation of the tax which may be levied for payment of the costs of the completion of the proposed works and improvements shown in any supplemental plan for reclamation shall apply to the amount of the benefits as readjusted. There shall be no such readjustment of benefits more often than once in a year. The list of lands, and other property, with the readjusted assessed benefits and the order of the county commission, shall be filed in the office of the county recorder. The petition for reassessment of benefits may request that the cost of the improvement be payable in more than one installment and if the county commission agrees in its order of assessment, the assessment shall be payable in the number of installments, not exceeding fifteen, so found to be desired, which installments shall be equal, and each tract of land in the district shall be charged with interest which shall be apportioned against the lands in the district by the same rule of apportionment as the principal assessment.