(a)Applicability. Any rate charged for transportation service under subparts B and G of this part must be established under a rate schedule that is filed with the Commission prior to commencement of such service and that conforms to the requirements of this section.(b)Rate objectives. Maximum rates for both peak and offpeak periods must be designed to achieve the following three objectives: (1) Rates for service during peak periods should ration capacity;(2) Rates for firm service during off-peak periods and for interruptible service during all periods should maximize throughput; and(3) The pipeline's revenue requirement allocated to firm and interruptible services should be attained by providing the projected units of service in peak and off-peak periods at the maximum rate for each service.(c)Rate design -(1)Volumetric rates. Except as provided in § 284.7(e) , any rate filed for service subject to this section must be a one-part rate that recovers the costs allocated to the service to the extent that the projected units of that service are actually purchased and may not include a demand charge, a minimum bill or minimum take provision or any other provision that has the effect of guaranteeing revenue. Such rate must separately identify cost components attributable to transportation, storage, and gathering costs.(2)Based on projected units of service. Any rate filed for service subject to this section must be designed to recover costs on the basis of projected units of service. The fixed costs allocated to capacity reservations, as determined in accordance with § 284.7(e) , should be used along with the projected nominations accepted by the pipeline to compute the unit reservation fee. The remaining fixed costs and all variable costs should be used to determine the volumetric rate computed on the basis of projected volumes to be transported. The units projected for the service in rates filed under this section may be changed only in a subsequent rate filing under section 4 of the Natural Gas Act.(3)Differentiation due to time and distance. Any rate filed for service subject to this section must reasonably reflect any material variation in the cost of providing the service due to:(i) Whether the service is provided during a peak or an off-peak period; and(ii) The distance over which the transportation is provided.(4)Cost basis for rates.(i) Any maximum rate filed under this section must be designed to recover on a unit basis, solely those costs which are properly allocated to the service to which the rate applies.(ii) Any minimum rate filed under this section must be based on the average variable costs which are properly allocated to the service to which the rate applies.(5)Rate flexibility.(i) Any rate schedule filed under this section must state a maximum rate and a minimum rate.(ii)(A) Except as provided in paragraph (d)(5)(ii)(B) of this section the pipeline may charge an individual customer any rate that is neither greater than the maximum rate nor less than the minimum rate on file for that service.(B) If a pipeline does not hold a blanket certificate under Subpart G of this part, it may not charge, in a transaction involving its marketing affiliate, a rate that is lower than the highest rate it charges in any transaction not involving its marketing affiliate.(iii) The pipeline may not file a revised or new rate designed to recover costs not recovered under rates previously in effect.Order 436, 50 FR 42493, Oct. 18, 1985, as amended at 50 FR 52274, Dec. 23, 1985; 53 FR 22163, June 14, 1988; Order 522, 55 FR 12169, Apr. 2, 1990; Order 581, 60 FR 53072, Oct. 11, 1995. Redesignated and amended by Order 637, 65 FR 10220 , Feb. 25, 2000 Order 436, 50 FR 42493, 10/18/1985, as amended at 50 FR 52274, 12/23/1985; 53 FR 22163, 6/14/1988; Order 522, 55 FR 12169, 4/2/1990; Order 581, 60 FR 53072, 10/11/1995. Redesignated and amended by Order 637, 65 FR 10220 , 2/25/2000