Permits and registrations for units that existed before the comprehensive rule revisions in this chapter as adopted in 2006 (2006 Revisions) to this subchapter became effective remain valid, except as provided by this subchapter. If existing authorizations do not comply with the 2006 Revisions, the permittee or registrant is under an obligation to apply for a modification not subject to public notice in accordance with §305.70(l) of this title (relating to Municipal Solid Waste Permit and Registration Modifications) within 180 days to comply with the 2006 Revisions to this subchapter. Timely submission of an application to modify qualifies the owners or operators of existing units to operate under requirements contained in the existing authorization until a final decision is made on the application.