Image of back arrow Back to filtered results

XRN 5072
Application and derivation of TTZ indicator and calculation of volume and energy – all classes

Last Updated
24 Jan 2022
Release Type
Implementation Date
22 Jan 2022
Proposer Xoserve Impacted DSC service area

Service Area 3 (Previous Dec 18 – Mar 21)

Record/submit Data in Compliance with UNC

Customer Change Team Leader


This proposal is required to amend the logic to how the system derives the Round the Clock (RTC) or Though The Zero (TTZ) count.

  1. Where there is a Class 4 site with AMR/DRE installed, check to check reconciliation is carried out when Site Visit Reads are received.

When an RGMA update is received (ONJOB or ONUPD) these reads are treated as Site Visit Reads.

When an ONUPD (asset update) is submitted the shipper does not have to supply any meter reads or Round the Clock (RTC) count or TTZ count (Through The Zeros) so Xoserve will generate estimated reads and derive a RTC if required.  If the shipper is submitting an RGMA flow (ONJOB) and where the RTC is not supplied, the system will derive a RTC count.

When the system looks to derive the RTC count it will be based on the Read history (last Actual read, last Check Read, AMR/DRE Installation read, Meter Install read, etc) For Project Nexus the RGMA design was taken from legacy CA Rules.  The RGMA logic was considered as an ‘As Is’ process and the requirements were not changed.  Under source rule 100278 it states “If the RTC is not provided, the RTC would be derived with an increment.

We have seen instances where an RTC count of 1 is incorrect, as previous read history shows that the meter has gone round the clock several times. This has generated a reduced volume and energy, so has caused the AQ value to be understated and incorrect Reconciliation. This understated AQ affects all downstream processes that use the AQ value, (EUC assignment, daily allocation and the calculation of unidentified Gas).

Impacted Customer Types

  • Shipper
  • Supplier


Document title Last updated Type
XRN5072 Change Proposal 05/Aug/2021 PDF
XRN5072 HLSO 11/Dec/2020 PDF


Initial Review
Change Proposal Raised 02/01/20
Status Awaiting ChMC approval
Approved to Capture 08/01/20
Status ChMC approved into Capture
Solution Consultation
Change Pack Issued 14/12/20
Status ChMC approved solution 13/01/2021
Awaiting Delivery
Stage not used 00/00/00
Status Change moved directly to In Delivery
In Delivery
Release Nov 21 Detail Design Change Pack reissued 17/05/21
Status ChMC approved design 07/04/2021 reissued for information in May 17/05/2021 and July 12/07/2021
Expected: 22/01/22
Status Successfully Implemented

Contact the Change Team

Need to get in touch with a member of the Change Team?

You can email us at: and we'll get back on the same day between the hours of 9:00am to 4:30pm.