MarkWest Pioneer, L.L.C.

Original Volume No. 1

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Effective Date: 04/01/2009, Docket: RP09-321-000, Status: Effective

Original Sheet No. 74 Original Sheet No. 74

GENERAL TERMS AND CONDITIONS

(Continued)

16. DISCOUNTED RATES

16.1. Transporter has the right to discount its rate from the maximum rates set

forth on the Statement of Rates and Charges, provided such rate is not below

the stated minimum rate. In the event that Transporter agrees to discount

its rate to Shipper below Transporter’s maximum rate under Transporter’s

Rate Schedules, the applicable discount terms may be reflected on the FT or

IT Agreement(s) and will apply without the discount constituting a material

deviation from Transporter’s applicable FT or IT Agreements.

16.2. Order of Discounting - To the extent Transporter discounts the rates for

service, the rates for service will be deemed to have been discounted in the

following order: (1) Reservation Charge; and (2) Commodity Charge, but no

charges will be discounted below the stated minimum rate.

17. ANNUAL CHARGE ADJUSTMENT

17.1. Purpose - This section is filed pursuant to Section 154.402 and Subpart B of

Part 382 of the Commission’s Regulations under the Natural Gas Act (“NGA”).

The intent and purpose of this section is to establish an Annual Charges

Adjustment (“ACA”) provision under which Transporter can recover from its

customers annual charges assessed to it by the Commission pursuant to Part

382 of the Commission’s Regulations. All amounts assessed pursuant to Part

382 of the Commission’s Regulations shall be recorded in Account 928.