(1) No provider of regulated telecommunications service may use current revenues earned or expenses incurred in conjunction with a regulated service to subsidize a not regulated service. The accounting records of the provider shall be kept in a manner that provides adequate information to detect cross-subsidization. The commission has the authority to determine the proper assignment or allocation of revenues, expenses and common investment between regulated and not regulated service.

(2) Commission review to determine the proper allocation between regulated and not regulated service may be in a rate case or the commission may initiate an investigation.

(3) A fully allocated cost accounting or tracking system shall be implemented by each telecommunications provider to separate all revenues and costs that are regulated by this commission.

(a) If the commission finds it necessary it may require a telecommunications provider to maintain entirely separate records and accounts of regulated telecommunications service.

(4) On finding that a regulated service is subsidizing a not regulated service the commission may eliminate the subsidy by any method it deems appropriate.

(5) Nothing in Title 69, Chapter 3, Part 8 precludes the commission from exercising its authority under 69-3-202, MCA.