The assessments for maintenance and repair made pursuant to § 14-91-601 may be in addition to the twenty percent (20%) maximum assessment permitted for the original cost of the improvement by § 14-90-801, but no additional assessment shall be made in excess of five percent (5%) of the value of the real property in the district as shown by the last county assessment, and not more than ten percent (10%) of the additional assessment of benefits shall be collected in any one (1) year.