(a) After a municipality has by ordinance approved an economic development plan and established an economic development project area, the plan may be amended and the boundaries of the area may be altered only as provided in this Section. Amendments that (i) alter the exterior boundaries of the proposed economic development project area, (ii) substantially affect the general land uses proposed in the proposed economic development plan, or (iii) substantially change the nature of the proposed economic development project shall be made only after notice and a hearing under the procedures set forth in this Act.
     (b) Amendments that do not (i) alter the exterior boundaries of a proposed economic development project area, (ii) substantially affect the general land uses proposed in the proposed economic development plan, or (iii) substantially change the nature of the proposed economic development project may be made without further hearing, provided that the municipality shall give notice of its changes by mail to each affected taxing district and by publication in a newspaper or newspapers of general circulation within the affected taxing district. The notice by mail and by publication shall each be given not later than 10 days following the adoption by ordinance of the amendment.