From and after October 18, 1991, in order to increase the maximum allowable monthly tonnage handled at a Class A facility by an aggregate amount of more than ten percent of the facility's permit tonnage limitation within a two-year period, the permittee shall:
(1) File an application for approval with, and obtain approval from, the county or regional solid waste authority for the county or counties in which the facility is located. Such application shall be a modification of the Class A facility's certificate of site approval. The county or regional solid waste authority shall act upon such application and either grant or deny it within thirty days after the application is determined by the county or regional solid waste authority to be filed in a completed manner; and
(2) File an application for approval with, and obtain approval from, the Public Service Commission to modify the certificate of need in the manner set forth in section one-c, article two, chapter twenty-four of this code.