(b) The activities approved in a permit issued pursuant to s. 373.4145, 1994 Supplement to the Florida Statutes 1993, and the review of activities proposed in applications received and completed before the effective date of the rules adopted under subsection (1), as applicable. This paragraph shall also apply to any modification of the plans, terms, and conditions of a permit issued pursuant to s. 373.4145, 1994 Supplement to the Florida Statutes 1993, that lessens the environmental impact, except that any such modification shall not extend the time limit for construction beyond 2 additional years. This subsection shall not apply to any activity that is altered, modified, expanded, abandoned, or removed after adoption of the applicable rules under subsection (1).