(1)    In this section, “basic network function” means the smallest disaggregation of local exchange transport, switching and loop functions that is capable of being separately listed in a tariff and offered for sale.

   (2)   In this chapter, total service long-run incremental cost is calculated as the total forward-looking cost, using least cost technology that is reasonably implementable based on currently available technology, of a telecommunications service, relevant group of services, or basic network function that would be avoided if the telecommunications provider had never offered the service, group of services, or basic network function or, alternatively, the total cost that the telecommunications provider would incur if it were to initially offer the service, group of services, or basic network function for the entire current demand, given that the telecommunications provider already produces all of its other services.