The Council shall prescribe by general ordinance the complete special assessment procedure concerning the initiation of projects, plans and specifications, estimates of cost, notice of hearings, making and confirming assessment rolls for the improvement, the correction of errors in the assessment rolls, collections of special assessments, the assessment of single lots or parcels, and any other matters concerning the making of improvements by the special assessment method, subject to the provisions of this Charter and the laws of the State. The ordinance shall authorize additional assessments, if the prior assessment proves insufficient to pay for the improvement or is determined to be invalid, in whole or in part.