(1) keep performance records and retain them as specified by Part 651 of this Title for each entity level as defined in section 603.3 of this Part and maintained in a manner that permits audit by commission staff; and

(2) measure answer time performance as defined in section 603.3 of this Part, for customer service centers that receive a monthly average of more than 275 calls per working day for three consecutive months. Excluded from this provision is any group of specialized business account representatives established to address the needs of a single large business customer, or a small group of such customers.