MountainWest Pipeline, LLC is indirectly owned by the The Williams Companies, Inc. through Williams Partners Operating LLC which directly owns MountainWest Pipelines Holding LLC.

White River Hub, LLC is owned 50% by MountainWest White River Hub, LLC and 50% by Enterprise White River Hub, LLC.

Dockets CP91-2021 / CP97-49

Dockets CP95-115 / CP97-49

CP05-5 / CP07-25.

Reconciliation of Plant & Provision Accounts:

Includes Book Cost of Plant Retired - 101 (pg 209 line 129, col. d)			$	15,843,220.00

Inventory in account 117.1 represents the balance of recoverable gas volumes that are necessary to maintain pressure and deliverability requirements for MountainWest Pipeline’s storage facilities. Recoverable base gas is reported under the inventory method.

Inventory in account 117.2 represents the balance of system balancing gas volumes for load balancing, no notice transportation, and other operational purposes. System balancing gas is reported under the inventory method.

Inventory in account 117.4 represents volumes owed to the system and volumes lent to the system in a park and loan agreement, reported at market (estimated replacement) value.

Inventory in account 164.1 represents the balance of pipeline owned gas which the pipeline intends to sell. Pipeline owned gas is reported under the inventory method.

Description			2025
Equity Earnings from 100% of MWOT's Net Income			$	48,453,390

Description			2025
Equity Earnings from 100% of MWFS's Net Loss			$	848,549

Description			2025
Equity Earnings from 50% of WRH's Net Income			$	2,817,755

Description			2025
Distribution to Parent			$	(3,178,666)

CTD DESCRIPTION			DEFERRED TAX ACCOUNT			12/31/2025 Balance
PROPERTY, PLANT, & EQUIPMENT			190			5,053,341
REGULATORY LIABILITIES			190			14,443,975
ENVIRONMENTAL LIABILITIES			190			14,571
OTHER ACCRUED LIABILITIES			190			3,411,363
190 TOTAL						22,923,251

Account Description			2025
Total of Accounts 427 on Page 116			$	19,136,652
427 Less: Amortization of Cash Flow Hedge Deferrals related to notes in Acct. 224			(966,652)
			$	18,170,000

(a) Use tax is distributed to various accounts based on the accounts coded on the originating invoice.

CTD DESCRIPTION			DEFERRED TAX ACCOUNT			12/31/2025 Balance
PROPERTY, PLANT, & EQUIPMENT			282			21,138,539
282 TOTAL						21,138,539

CTD DESCRIPTION			DEFERRED TAX ACCOUNT			12/31/2025 Balance
REGULATORY ASSETS			283			6,727,943
DEFERRED CHARGES & OTHER ASSETS			283			672,230
283 TOTAL						7,400,173

Docket RP95-407

Balance reflects MountainWest Pipeline’s excess deferred income taxes (EDIT) resulting from the reduction in the federal corporate income tax rate under Tax Cuts and Jobs Act of 2017 (TCJA).

FERC GAS TARIFF PT. 1 GENERAL TERMS & CONDITIONS SECTION 12.6.

FERC GAS TARIFF PT. 1 GENERAL TERMS & CONDITIONS SECTION 12.15

FERC GAS TARIFF PT. 1 GENERAL TERMS & CONDITIONS SECTION 12.15

FERC GAS TARIFF PT. 1 GENERAL TERMS & CONDITIONS SECTION 1

FERC GAS TARIFF PT. 3 GENERAL TERMS & CONDITIONS SECTION 17

FERC GAS TARIFF PT. 3 GENERAL TERMS & CONDITIONS SECTION 16.4

FERC GAS TARIFF PT. 1 GENERAL TERMS & CONDITIONS SECTION 12.6

FERC GAS TARIFF PT. 3 GENERAL TERMS & CONDITIONS SECTION 17

In addition to the reported withdrawal volumes, there were 56,153,522 Dth injection volumes.

In addition to the reported withdrawal volumes, there were 43,613,540 Dth injection volumes.

PAL1 Daily Revenue - Account 489.4			$	2,116,772
PAL1 Delivery Revenue - Account 489.4			64,501
Total PAL1 Revenue			$	2,181,273

Balance represents withdrawal volume only. In addition to the reported withdrawal volume, the injection volume was 31,835,603 Dth.

Peaking Storage Service Revenue:
Reservation Revenue			$	6,366,792
Withdrawal Revenue			92,206
Injection Revenue			92,798
			$	6,551,796

Peaking Storage Service Volumes:
			Dth
Withdrawal Volumes			2,629,447
Injection Volumes			2,666,377
			5,295,824

Delivery Points:

MAP 176 - ROBERSON CREEK

MAP 281 - KANDA COL OTPL DEL

MAP 384 - EAKIN TO OTPL

MAP 388 - ROBERSON THRU KANDA

MAP 868 - XO-16 NWP DELIVERY

MAP 390 - OVERTHRUST 121/KRGT PAINTER FROM QPC

MAP 345 - KEMMERER GATE TO OTP

MAP 389 - HAMS FORK FROM QPC

MAP 207 - NAUGHTON

MAP 425 - BELL BUTTE STORAGE INJECTION VIA DEOP

MAP 424 - RUBY FROM QPC

MAP 445 – WARMSUTTER M&R FROM DEQP

Receipt Points:

MAP 285 - OVERTHRUST JL 36 MS

MAP 387 - OTPL TO QPC EAKIN

MAP 427 - WIC WAMSUTTER TO QPC

MAP 428 - OPAL PLANT TO QPC/WTNY

MAP 429 - OPAL PLANT TO QPC/EAKIN

MAP 430 - PIONEER PLT TO QPC/WTNY

MAP 431 – PIONEER PLT TO QPC/EAKIN

MAP 432 – WARMSUTTER (REC) TO QPC

MAP 433 – WIC RS TO QPC

MAP 434 – GRANGER OTPL TO QPC/WHITNEY

MAP 869 - OTPL TO QPC XO16

Delivery Points:

MAP 410 – WHITE RIVER HUB

Receipts Points:

MAP 409 – WHITE RIVER HUB

Underground Storage rates for lines 4 are based on the respective depreciable lives.

Transmission Plant rates for lines 7 & 10 are based on the respective depreciable lives.

General Plant rates for line 8 are based on the respective depreciable lives.

Intangible rate for line 9 is based on a 5-year depreciable basis.

Enterprise shared service costs for fleet leasing and other fleet costs are allocated to franchises via specific allocations based on labor costs assigned to capital work orders.

Employees' direct assignment payroll and non-payroll charges recorded to a specific work order for the benefit of the Transmission, Power & Gulf Operating Area that are not specific to a franchise are allocated to franchises included in the operating area via general allocations based on "Modified Massachusetts" formula (MMF).

Salt Lake City, Utah building rent is allocated based on employee labor hours.

Salt Lake City, Utah building rent is allocated based on employee labor hours.

MountainWest shared services costs are allocated to MountainWest Pipeline, LLC, MountainWest Overthrust Pipeline, LLC, White River Hub, LLC, and nonregulated companies via specific allocations for pipeline companies based on miles of pipe and general allocations for the other companies based on "Modified Massachusetts" formula (MMF).

Salt Lake City, Utah building rent is allocated based on employee labor hours.

Salt Lake City, Utah building rent is allocated based on employee labor hours.

Salt Lake City, Utah building rent is allocated based on employee labor hours.

Dth calculated using the 1.065 Mcf/Dth conversion factor. Applied to line 2, 3, 4 & 7 also.

Operator Balancing Agreement allocations

Peaking Storage

Operator Balancing Agreement allocations

Peaking Storage

Max deliverability for Chalk Creek assumes a BTU conversion of 1,044 BTU/SCF and a max rate of 35 MMscfd.

Max deliverability for Coalville assumes a BTU conversion of 1,024 BTU/SCF and a max rate of 65 MMscfd.

Max deliverability for Leroy assumes a BTU conversion of 1,026 BTU/SCF and a max rate of 75 MMscfd.

Max deliverability for Clay Basin assumes a BTU conversion of 1,065 BTU/SCF and a max rate of 765 MMscfd as limited by dehydration units.

Footnote to Instruction 5:

Mountain West Pipeline, LLC does not bundle Sales and Transportation Services.

Footnote to Instruction 7:

All quantities of gas were subject to Commission regulation.

Footnote to Instruction 9:

Mountain West Pipeline had the following storage quantities at 6/30/26:

Clay Basin Storage						Dth
Contract Storage						49,317,086
System Balancing Gas						1,197,811
Gas for Future Sale or Transportation						1,052,145
						51,567,042
Leroy Peaking Storage						Dth
Contract Storage						449,075
Coalville Peaking Storage						Dth
Contract Storage						362,336
Chalk Creek Peaking Storage						Dth
Contract Storage						13,569

This amount does not include System Balancing Gas withdrawals reported on Line 12, or 83,017 Dth of Gas Received for Fuel which is reported on Line 13.

This amount does not include System Balancing Gas withdrawals reported on Line 12, or 29,264 Dth of Gas Received for Fuel which is reported on Line 13.

System Balancing Gas withdrawals. Applies to column (d) also.

This amount has been reduced by the quantity of “Deliveries of Gas to Others for Transportation” (Line 26). Applies to column (d) also.

System Balancing Gas injections. Applies to column (d) also

Allocation method was based on throughput. Applies to lines 11, 18, and 26 also.

Shipper Supplied Gas, Gas Consumed in Pipeline Operations, and Net Excess or (Deficiency) balances are valued based on the "Inside FERC’s Gas Market Report" first-of-the-month posting for Northwest Pipeline Corp., Rocky Mountains, published for the first of the month following gas flow. Applies to lines 6, 11, 13, 18, and 26 also.

In accordance with FERC Order No. 581, Shipper Supplied Gas is not directly charged to an account. Any excess or deficiency in net Shipper Supplied Gas (line 37) is recorded as “Other Regulatory Assets/Liabilities” (Accounts 182.3 / 254) with offsetting entries booked to “Regulatory Debits/Credits”, (Accounts 407.3 / .4). Applies to months 2 & 3 also.

Allocation method was based on actual gas supplied and used. Applies to Line 13 also.

In accordance with FERC Order No. 581, Shipper Supplied Gas is not directly charged to an account.Applies to months 2 & 3 also.

Gas used for M&R Fuel, Mains Fuel, and other Operational Fuel. Applies to all other columns on this line.

“Net excess or (deficiency)” balances are refunded or collected in-kind through MountainWest Pipeline, LLC’s annual Fuel Gas Reimbursement and Tracking provision (§12.15) of the General Terms and Conditions of Part I of MountainWest Pipeline, LLC's FERC Gas Tariff. Applies to months 2 & 3 also.