1. Version 2 - 05/08/2008 The AQ calculation and validation process Compiled and delivered from the xoserve AQ Team for Review Group 209 Susan Prosser & Steve Nunnington.

2. Version 2 - 05/08/2008 System Calc process G0 to 3. G0 to 11. G0 to 5. G0 to 6.

3. Version 2 - 05/08/2008 Warnings Report Appendix 1 This is an example of how M Numbers appear within the Warnings Report as part of the AQ Review. Not all Warnings listed within this example

4. Version 2 - 05/08/2008 Warning Report Reasons  Reason Code and Message Text  MPQ 00031 - Meter Point is owned by xoserve. AQ not calculated  MPQ 00028 - Meter Point is not a part of Live Confirmation. AQ not calculated  MPQ 00029 - AQ not calculated due to the application of backstop date  RCN 00001 - Reconnection does not exist  MPQ 00030 - Reconnection Effective date is in the relevant metered period. AQ not calculated  MPQ 00025 - Meter Point not DM for whole of DM AQ Calculation Period. AQ not Calculated  GNT 00001 - Gas Nomination Type does not exist  MRF 00001 - Meter Reading Frequency does not exist  MPQ 00015 - Calculated annual quantity is negative  MRR 00001 - Meter read request does not exist  CPN 00323 - Consumption starts before earliest possible start meter read date  CPN 00320 - Consumption overlap. AQ not calculated  MRE 00480 - AQ not calculated due to the absence of reads since the previous AQ calculation  MRE 00481 - AQ not calculated due to the absence of reads since competition effective date  CPN 00304 - Consumptions for Meter Point are not contiguous  CPN 00321 - Negative consumption during metered period. AQ not calculated  CPN 00305 - Consumption start read more than three years before Target Opening Date or less than six months before Target End date  LCV 00001 - LDZ Calorific Value does not Exist  CPN 00322 - Insufficient Consumption Data to Calculate AQ (New MPRN)  CPN 00318 - Consumption gap. AQ not calculated  CPN 00303 - Consumption Start Date not equal to start Meter Reading date  SPO 00020 - Supply Point History not contiguous over whole of relevant metered period  MPC 00001 - Meter Point Configuration not found G0 to 2.

5. Version 2 - 05/08/2008 AQ Team Validations Appendix 2 G0 to2.

6. Version 2 - 05/08/2008 Spec Calc

7. Version 2 - 05/08/2008 Spec Calc Validations  ASI – AQ Spec calc requests.  When the supply point AQ for the provided MPRN is less than 1, it would be rejected with MPQ 00010  If all exchange details are provided and meter serial number is not provided, then STD 00137  If all exchange details are provided and imperial indicator is not provided, then STD 00139  If all exchange details are provided and exchange start reading date is null date, then STD 00143  If all exchange details are provided and exchange end reading date is null date, then STD 00145  If the start reading date is less than 01.03.1996, then it would be rejected with STD 00149  If the end reading date is less than 01.03.1996, then it would be rejected with STD 00150  If the exchange start reading date is less than 01.03.1996, then it would be rejected with STD 00151  If the exchange end reading date is less than 01.03.1996, then it would be rejected with STD 00152  Invalid Imperial Indicator (other than Y/N), rejects with STD 00154  Invalid Reading Units (other than 1,10,100,1000,10000), rejects with STD 00155  Invalid Exchange Reading Units (other than 1,10,100,1000,10000), rejects with STD 00156  Invalid Reading factor (other than 0.01,0.1,1,10,100), rejects with STD 00157  Invalid Exchange Reading factor (other than 0.01,0.1,1,10,100), rejects with STD 00158  Start reading is greater than processing date, reject with STD 00159  End reading is greater than processing date, reject with STD 00160  Exchange Start reading is greater than processing date, reject with STD 00161  Exchange End reading is greater than processing date, reject with STD 00162  Number of dials out of permitted range (ideal range is 4 to 12), reject with STD 00182  If the meter is Imperial, then reading factor and reading units must be in either of the following combinations: (0.01, 1), (0.1, 10), (1, 100), (10, 1000), (100, 10000). Reject if otherwise with MMO 00553  If the meter is metric, then reading factor and reading units must be in either of the following combinations: (1, 1), (10, 10). Reject if otherwise with MMO 00553  If the exchanged meter is Imperial, then reading factor and reading units must be in either of the following combinations: (0.01, 1), (0.1, 10), (1, 100), (10, 1000), (100, 10000). Reject if otherwise with MMO 00554  If the exchanged meter is metric, then reading factor and reading units must be in either of the following combinations: (1, 1), (10, 10). Reject if otherwise with MMO 00554  If the end reading is less than start reading, then reject with STD 00166  If the start reading date is less than the earliest supply point start date, then reject with STD 00183  If the supply point is end dated and if the end date is greater than the supply point end date, then reject with STD 00183  If the exchange start reading date must be equal to end reading date, otherwise reject with STD 00164  If the exchange end reading date is less than or equal to exchange start reading date, otherwise reject with STD 00165  Sum of read TTZ and exchange read TTZ count should not go beyond 99, otherwise reject with STD 00193  All the reading except the start reading date should be greater than competition effective date, otherwise reject with MRE 471  If the provided MPRN does not exist on the system, then reject with MPO 00001. Appendix 3

8. Version 2 - 05/08/2008 Is An AQ Amendme nt Required? AQ Amendments: Process Flow Xoserve Releases Notification Files To Shipper  SSP (NRQ)  Threshold Crossers (NRS)  LSP (NRM) Xoserve Releases Notification Files To Shipper  SSP (NRQ)  Threshold Crossers (NRS)  LSP (NRM) Shipper Analyses Information To Determine If Amendment is Required / Can Be Actioned Shipper Takes No Further Action xoserve Notifies Shipper of Revised AQ by 14th Sept: (  NRL  NRO) 1 st OCTOBER AQ BECOMES EFFECTIVE Shipper Submits Speculative Calculator Request File:  ASI File  T19 Record Shipper Submits Speculative Calculator Request File:  ASI File  T19 Record Spec Calc File Rejected with Rejection Reason:  ASO File will include S72 Rejection Record Spec Calc File Rejected with Rejection Reason:  ASO File will include S72 Rejection Record Shipper Receives Recalculated AQ Value Is AQ Acceptable and in Uniform Network Code Tolerances? Shipper Submits Amendment File as Per Spec Calc Response File:  AAI File  T17 Record Shipper Submits Amendment File as Per Spec Calc Response File:  AAI File  T17 Record xoserve Responds to Amendment File to Shipper: AAO File T18 Record AC, RJ or RF Outcome xoserve Responds to Amendment File to Shipper: AAO File T18 Record AC, RJ or RF Outcome Amendment File Rejected with Rejection Reason:  AAO File will include S72 Rejection Record Amendment File Rejected with Rejection Reason:  AAO File will include S72 Rejection Record Amendment File Accepted NO YES xoserve Responds with Speculative Calculation Response File to Shipper: ASO File T20 Record AC or RJ Outcome xoserve Responds with Speculative Calculation Response File to Shipper: ASO File T20 Record AC or RJ Outcome NO YES Is AQ Acceptable and in Uniform Network Code Tolerances? REJECT ACCEPT REJECT ACCEPT

9. Version 2 - 05/08/2008 Amendment Validations  AAI – AQ Amendment requests.  If the Meter Point is not part of any confirmation OR if the Shipper is not responsible for the provided MPRN, it would be rejected with SHI 00010.  If the provided confirmation reference is not the current live confirmation of the MPRN, it would be rejected with MPO 00024.  If smaller supply meter point is not eligible for AQ/WC amendment, then reject with STD 00177  If an outstanding amendment referral exists for an MPRN, it would be rejected with AQA 00018  If the requested AQ is less than 1, it would reject with STD 00178  If the start reading date is less than 01.03.1996, then it would be rejected with STD 00149  If the end reading date is less than 01.03.1996, then it would be rejected with STD 00150  If the exchange start reading date is less than 01.03.1996, then it would be rejected with STD 00151  If the exchange end reading date is less than 01.03.1996, then it would be rejected with STD 00152  Invalid Imperial Indicator (other than Y/N), rejects with STD 00153  Invalid Reading Units (other than 1, 10, 100, 1000, 10000), rejects with STD 00155  Invalid Exchange Reading Units (other than 1, 10, 100, 1000, 10000), rejects with STD 00156  Invalid Reading factor (other than 0.01, 0.1, 1, 10, 100), rejects with STD 00157  Invalid Exchange Reading factor (other than 0.01, 0.1, 1, 10, 100), rejects with STD 00158  Start reading is greater than processing date, reject with STD 00159  End reading is greater than processing date, reject with STD 00160  Exchange Start reading is greater than processing date, reject with STD 00161  Exchange End reading is greater than processing date, reject with STD 00162  Invalid Manual check flag (other than Y/N), reject with STD 00163  Number of dials out of permitted range (ideal range is 4 to 12), reject with STD 00182  If reading unit, reading factor and imperial indicator are inconsistent, then reject with MMO 00533  If exchange reading unit, reading factor and imperial indicator are inconsistent, then reject with MMO 00534  If the end reading is less than start reading, then reject with STD 00166  If the start reading date is less than the earliest supply point start date, then reject with STD 00183  If the supply point is end dated and if the end date is greater than the supply point end date, then reject with STD 00183  If the exchange start reading date must be equal to end reading date, otherwise reject with STD 00164  If the exchange end reading date is less than or equal to exchange start reading date, otherwise reject with STD 00165  If exchange TTZ is 0 and if the exchange end reading date is less than exchange start reading date, otherwise reject with STD 00167  Sum of read TTZ and exchange read TTZ count should not go beyond 99, otherwise reject with STD 00193  If the shipper is not responsible for the MPRN, it would be rejected with SHI 0010

10. Version 2 - 05/08/2008 Amendment Validations  All the readings except the start reading date should be greater than competition effective date, otherwise reject with MRE 471  If the current and proposed market sector is Domestic, then 20% amendment tolerance rule is applied. Meter AQ changes will be accepted only if it lies beyond the tolerance range with respect to xoserve calculated initial AQ. Reject reason provided is AQA 00019  The requested AQ value (provided in the file) and the derived AQ (using the parameters in the file) should match, otherwise reject with STD 00179  If the MPRN is primary and if either the current or proposed market sectors is I&C, then refer the amendment, otherwise reject it with MPO 00587.  If the provided MPRN does not exist on the system, then reject with MPO 00001.  If the start read date is not later than AQ-WC backstop date, then reject with STD 00217  If the end read date is earlier than xoserve calculated end read date, then reject with STD 00216  Outstanding AQ/WC Appeal referral exists for this meter point, then reject with AML 00018  Insufficient information to calculate AQ, then reject with AQA 00016  Consumption period less than 6 month, then reject with MRE 00470  Post code not found, then reject with POC 00011  Start reading/date not consistent with UKLink, then reject with RRR 00010  End reading/date not consistent with UKLink, then reject with RRR 00011  Exchange start read/date not consistent with UKLink, then reject with RRR 00012  Exchange end read/date not consistent with UKLink, then reject with RRR 00013  TTZ count incorrect, then reject with RRR 00014  Meter exchange not identified on amendment/appeal, then reject with RRR 00015  Manual referral with insufficient supporting information, then reject with RRR 00016  Appeal window not currently open for request, then reject with RRR 00017  Exchange meter serial number not provided, then reject with STD 00137  Exchange start reading date not provided, then reject with STD 00143  Exchange end reading date not provided, then reject with STD 00145  Occurrence of DM since start reading date, then reject with STD 00171  Invalid value for number of dials or digits, then reject with STD 00181  Meter point was not part of a live supply point for entire consumption period, then reject with STD 00183  DM meter point cannot be appealed/amended to an AQ below the domestic threshold, reject with SPO 00013 G0 to 2.

11. Version 2 - 05/08/2008 Can An AQ Appeal Be Raised? Can an AQ Appeal be raised? AQ Appeals: Process Flow Shipper determines current AQ value is not reflective of actual consumption Shipper unable to raise AQ Appeal – AQ will be recalculated during next AQ Review – Shipper will have opportunity to raise Amend Shipper Submits Speculative Calculator Request File:  ASI File  T19 Record Shipper Submits Speculative Calculator Request File:  ASI File  T19 Record Spec Calc File Rejected with Rejection Reason:  ASO File will include S72 Rejection Record Spec Calc File Rejected with Rejection Reason:  ASO File will include S72 Rejection Record Shipper Receives Recalculated AQ Value Is AQ Acceptable? Shipper Submits Appeal File as Per Spec Calc Response File:  API File  T17 Record Shipper Submits Appeal File as Per Spec Calc Response File:  API File  T17 Record xoserve Responds to Appeal File to Shipper: APO File T18 Record AC, RJ or RF Outcome xoserve Responds to Appeal File to Shipper: APO File T18 Record AC, RJ or RF Outcome Amendment File Rejected with Rejection Reason:  APO File will include S72 Rejection Record Amendment File Rejected with Rejection Reason:  APO File will include S72 Rejection Record Shipper Receives Appeal File and submits re-nomination & confirmation using Appeal Reference NO YES xoserve Responds with Speculative Calculation Response File to Shipper: ASO File T20 Record AC or RJ Outcome xoserve Responds with Speculative Calculation Response File to Shipper: ASO File T20 Record AC or RJ Outcome NO YES Is AQ Acceptable? REJECT ACCEPT REJECT ACCEPT AQ Goes live on xoserve System on Confirmation Effective Date

12. Version 2 - 05/08/2008 Appeal Validations  Appeal process specific Validations  Reject with AML 00017 error in case there is a mismatch between provided appeal level (T41/T43) and detail level (T17/T21) confirmation reference numbers  If the Meter Point does not belong to the confirmation reference identified on the T41/T43 record, reject with AML 00015.  If the provided confirmation reference number does not exist on the system, reject with CNF 00001  If duplicate T17/T21 records are sent under a same T41/T43 record. Reject with AML 00016  If any of the meter point are rejected on the appeal then, the appeal is rejected with AML 00012  There must be at least one T17 / T21 records to process the appeal, otherwise reject with APL 00014  If the current and the proposed market sectors are Domestic, then reject the appeal with APL 00015  If the WC appeal start date does not fall into the winter period, reject with WTC 00014  If the WC appeal end date does not fall into the winter period, reject with WTC 00015  If the current and proposed market sector is Domestic, then 20% appeal tolerance rule is applied. Meter WC changes will be accepted only if it lies beyond the tolerance range with respect to xoserve calculated initial AQ. Reject reason provided is WTC 00016  Reject all AQ appeals between the period 01-AUG to 15-SEP as part of AQ review process. The appeals received during this period are rejected with STD 00192  WC Appeals from Shippers are rejected with APL 00012  If the provided confirmation is not in either LI or CO status, reject with CNF 00003  If the Shipper is not the current registered owner of the MPRN, reject with SHI 00010  If the provided nomination shipper reference is not valid, reject with CNF 00010  DM meter point cannot be appealed/amended to an AQ below the domestic threshold, reject with SPO 00013