‘Sec. B-43. 36 MRSA §2557,  as amended by PL 2009, c. 204, §13 and c. 211, Pt. B, §32, is further amended by adding at the end a new paragraph to read:

For the purposes of subsections 33 and 34, in determining whether a particular customer is a business or nonbusiness customer, a telecommunications company may rely upon existing customer classifications maintained in its books and records, such as "individual," "consumer," "enterprise," "business," "corporate" or "government." A telecommunications company is not required to change the customer classifications the telecommunications company maintains in its books and records. If as a result of an audit a telecommunications company is required to change a customer's status to that of a business customer or to a nonbusiness customer for purposes of applying the tax, the change applies prospectively only.’