(a) Southwestern Bell Telephone Company. When any exchange is served by a central office or offices located in an adjacent state and the lesser of ten percent (10%) or five hundred (500) of the customers served by such exchange are located in Oklahoma, except when the exchange has fewer than five hundred (500) customers the ten percent (10%) limitation shall not apply, the basic local exchange services within the Oklahoma portion of such exchange shall be furnished at the rates and charges prescribed for the adjacent state within which such central office or offices are located; provided that:

1. (1) The Company shall file all pleadings with this Commission within ten (10) days subsequent to filing the pleadings with the adjacent state within which such central office or offices are located, or within ten (10) days of the effective date of this Section.
2. (2) The Company shall include with the notice an impact statement as directed by this Commission.
3. (3) The rates and charges prescribed by an order of the Regulatory Agency of such adjacent state, after a hearing on the merits has been held in such adjacent state, shall be filed with the Corporation Commission of the State of Oklahoma.
4. (4) Unless this Commission, within thirty (30) days after filing of the rates and charges approved by the adjacent state, determines that additional hearings are required to either accept or reject such rates and charges, then such rates and charges shall become lawfully effective for the Oklahoma customers served by such exchange upon the same date when such rates and charges are effective in the adjacent state.

(b) Other Telephone Companies with multi-state exchanges. When any exchange is served by a central office or offices located in an adjacent state and the lesser of ten percent (10%) or five hundred (500) of the customers served by such exchange are located in Oklahoma, except when the exchange has fewer than five hundred (500) customers the ten percent (10%) limitation shall not apply, the rates, charges and terms and conditions of service within the Oklahoma portion of such exchange shall be those prescribed by the Regulatory Agency of the adjacent state within which such central office or offices are located; provided that:

1. (1) The Company shall file all pleadings with this Commission within ten (10) days subsequent to filing the pleadings with the adjacent state within which such central office or offices are located, or within ten (10) days of the effective date of this Section.
2. (2) The Company shall mail notice to the customers located within Oklahoma stating that the customer may contact the Oklahoma Corporation Commission regarding any objections to the proposed rate increase.
3. (3) The Company shall include with the notice an impact statement as directed by this Commission.
4. (4) Unless this Commission, within thirty (30) days after filing of the rates and charges approved by the adjacent state, determines that additional hearings are required to either accept or reject such rates and charges, then such rates and charges shall become lawfully effective for the Oklahoma customers served by such exchange upon the same date when such rates and charges are effective in the adjacent state.