Questar Overthrust Pipeline Company

Second Revised Volume No. 1-A

Effective Date: 01/01/2008, Docket: RP08-142-000, Status: Effective

1st Rev. Second Revised Sheet No. 21 1st Rev. Second Revised Sheet No. 21 : Effective

Superseding: Second Revised Sheet No. 21

RATE SCHEDULE IT

INTERRUPTIBLE TRANSPORTATION SERVICE

(a) Usage Charge. Shipper shall pay the appropriate usage

charge for all gas delivered by Overthrust for transportation. The usage

charge shall be set forth in the transportation service agreement or any

amendment, and shall be no more than the maximum nor less than the minimum

rate specified in the Statement of Rates.

(b) Unauthorized Overrun Charge. Shipper shall pay the

unauthorized overrun charge set forth on Overthrust's Statement of Rates for

all unauthorized quantities of gas transported by Overthrust.

facilities shall be paid by Shipper according to § 25 of the General Terms

and Conditions.

(d) Cashout. Shipper will be subject to the balancing and

cashout provisions according to § 16 of the General Terms and Conditions.

(e) Other Charges. Overthrust shall charge Shipper for any

other FERC-approved charges that may apply to service under this rate

schedule.

(f) Fuel Reimbursement. Shipper shall reimburse Overthrust in

kind for gas used, lost, gained or unaccounted-for gas according to § 35 of

the General Terms and Conditions and the Statement of Rates.

3.2 Rate Changes. Overthrust may from time to time file with the FERC

to change the rates set forth on the Statement of Rates applicable to service

under this rate schedule. Overthrust shall be entitled to implement such

changed rates for service rendered to Shipper under this rate schedule on

their effective dates, subject to such refunds, surcharges or other

conditions that are specified as terms of the transportation service

agreement or that are permitted or required by the FERC. Nothing in this

section limits Shipper's rights to contest such changes, nor limits the

rights of Shipper and Overthrust to provide for lawful changes in rates

through the terms of the transportation service agreement.

3.3 Flexible Rates. Nothing in this tariff limits Overthrust's right

to implement different rates in