Southwest Gas Storage Company

First Revised Volume No. 1

Effective Date: 12/15/1999, Docket: RP00- 58-000, Status: Effective

Original Sheet No. 139 Original Sheet No. 139 : Effective

GENERAL TERMS AND CONDITIONS

(Continued)

12.STATEMENTS AND PAYMENTS

12.1 Southwest shall send to Shipper, on or before the 9th Business Day

of each month, a billing of charges for service rendered in the

preceding month. Such charges may be based on estimated

Quantities if actual Quantities are unavailable in time to prepare

the billing. In that event, Southwest shall provide, in the

succeeding month's billing, an adjustment based on any difference

between actual Quantities and estimated Quantities. Quantities at

points where operational balancing agreements exist should be

invoiced based on scheduled quantities.

12.2 Shipper shall pay Southwest within ten (10) days from the date on

which the bill is sent for all charges billed in accordance with

the provisions of the applicable Rate Schedule and these General

Terms and Conditions. Should Shipper fail to pay part or all of

the amount of any such bill, interest thereon shall accrue at an

average prime interest rate computed in a manner consistent with

Section 154.501(d) of the Commission's Regulations, from the due

date until date of payment.

If such failure to pay continues for thirty (30) days after

payment is due, then Southwest, in addition to any other remedy it

may have, may suspend further receipt and/or redelivery of gas

until such amount is paid after Southwest provides Shipper with

twenty (20) days prior written notice.

12.3 In the event that an error is discovered in the invoiced amount

hereunder, such error shall be adjusted within thirty (30) days of

the determination thereof, provided that claim therefor shall have

been made in writing.

(A) Measurement data corrections should be processed within 6

months of the production month with a 3 month rebuttal

period.

(B) The time limitation for disputes of allocations should be 6

months from the date of the initial month-end allocation with

a 3-month rebuttal period.