Section 5
SEC. 5. Section six of Commonwealth Act. Numbered Three hundred ninety-six is amended to read as follows: "SEC. 6. Upon the approval of the special assessment ordinance the Assessor and Collector concerned shall forthwith proceed to determine die special tax payable by each realty each year during die period fixed in the ordinance, upon the basis of the estimated or actual costs of die work and the total and parcel value of the real estate comprised within the district especially benefited, and shall notify each owner by ordinary mail of the special tax assessed against such property owned by him in the district benefited; but if upon the completion of the improvement, in cases where the assessment i s made prior to the completion thereof,it should appear that, the cost has been less or more, the City or the district engineer concerned through the Di rector of Public Works, shall forthwith certify this fact to the Assessor and Collector who shall thereupon proceed to rectify the assessment, redicing or increasing, as the case may be, the special tax upon each property affected for the unpaid remainder of the annual installments, or if all are paid, fixing the amount to be credited to or the special additional tax to be collected from the realty, as the case may be, and shall notify die persons interested of such rectification."