Section 4Y. Any subscription certificate under an individual or group medical service agreement which provides hospital expense and surgical expense insurance, delivered, issued or renewed by agreement between the insurer and the policyholder, within or without the commonwealth, shall provide benefits for residents of the commonwealth and to all group members having a principal place of employment within the commonwealth for the expenses incurred in the medically necessary diagnosis and treatment of speech, hearing and language disorders by individuals licensed as speech–language pathologists or audiologists under chapter 112, if such services are rendered within the lawful scope of practice for such speech–language pathologists or audiologists regardless of whether the services are provided in a hospital, clinic or private office; provided, however, that such coverage shall not extend to the diagnosis or treatment of speech, hearing and language disorders in a school–based setting. The benefits provided by this section shall be subject to the same terms and conditions established for any other medical condition covered by such individual or group medical service agreement.