(a) In this subchapter, "minor change" means a change, including the restructuring of rates of existing services, that:
(1) decreases the rates or revenues of an incumbent local exchange company; or
(2) together with any other rate change or approved tariff changes in the 12 months preceding the effective date of the proposed change, increases the company's total regulated intrastate gross annual revenues by not more than five percent.
(b) With regard to a change to a basic local access line rate, a "minor change" does not include a change that, together with any other change to the basic local access line rate that took effect during the 12 months preceding the effective date of the proposed change, results in an increase of more than 50 percent.