(a) Joint costs shall be grouped in cost pools for allocation to NPSL and non-NPSL operations in reasonable proportion to the beneficial or causal relationships which exist between a specific cost pool and the operations. That portion of a joint cost pool that may be allocated to NPSL operations is called an allocable joint cost.

(b) The following allocation principles apply in allocating joint costs:

(1) G & G. G & G shall be allocated on a line mile per tract basis.

(2) Wages and salaries. Wages and salaries that are not charged as direct on the basis of time spent on a particular job shall be allocated on a reasonable and equitable basis.

(3) Compensated personal absence, payroll taxes and personal expenses. These items shall be allocated on the same basis as wages and salaries.

(4) Transportation costs. Transportation costs for employees that are not charged direct shall be allocated on the same basis as their wages and salaries.

(c) Joint credits shall be allocated in the same manner as joint costs.

(d) When the NPSL is made a part of a unit, the allowed costs shall be charged to the NPSL capital account on the basis specified in the unit operating agreement as approved by the BSEE Director. Revenues and other credits shall be made to the NPSL accounts on the same basis as specified in the approved operating agreement. Joint costs of an NPSL and a non-NPSL tract that are adjacent to one another and are on the same structure shall be allocated on a basis approved by the BSEE Director.