47 C.F.R. § 61.40

(a) The Commission uses a variety of tools to determine whether a dominant carrier's private line tariffs are just, reasonable, and nondiscriminatory. The dominant carrier's burden of cost justification can be reduced when its private line rate structures comply with the following five guidelines.

(1) Rate structures for the same or comparable services should be integrated;

(2) Rate structures for the same or comparable services should be consistent with one another;

(3) Rate elements should be selected to reflect market demand, pricing convenience for the carrier and customers, and cost characteristics; a rate element which appears separately in one rate structure should appear separately in all other rate structures;

(4) Rate elements should be consistently defined with respect to underlying service functions and should be consistently employed through all rate structures; and

(5) Rate structures should be simple and easy to understand.

(b) The guidelines do not preclude a carrier, in a given case when a private line tariff does not comply with these guidelines, from justifying its departure from the guidelines and showing that its tariff is just, reasonable, and nondiscriminatory.