In addition to the requirements of subparts A and B of this part, the following must be included with the filing of any tariff, executed service agreement, or part thereof, that changes or supersedes any tariff, contract, or part thereof, on file with the Commission.

A list in the transmittal letter of the tariff sheets or sections being revised and a marked version of the sheets or sections to be changed or superseded showing additions and deletions. New numbers and text must be marked by either highlight, background shading, bold, or underline. Deleted text and numbers must be indicated by strike-through. Only those revisions appropriately designated and marked constitute the filing. Revisions to unmarked portions of the rate schedule or tariff are not considered part of the filing nor will any acceptance of the filing by the Commission constitute acceptance of such unmarked changes.

Documentation whether in the form of workpapers, or otherwise, sufficiently detailed to support the company's proposed change.

The documentation must include but is not limited to the schedules, workpapers, and supporting documentation required by these rules and regulations and the Commission's orders.

All rate changes in the filing must be supported by step-by-step mathematical calculations and sufficient written narrative to allow the Commission and interested parties to duplicate the company's calculations.

Any data or summaries included in the filing purporting to reflect the books of account must be supported by accounting workpapers setting forth all necessary particulars from which an auditor may readily verify that such data are in agreement with the company's books of account. All statements, schedules, and workpapers must be prepared in accordance with the classifications of the Commission's Uniform System of Accounts. Workpapers in support of all adjustments, computations, and other information, properly indexed and cross-referenced to the filing and other workpapers, must be available for Commission examination.

Where a rate, cost, or volume is derived from another rate, cost, or volume, the derivation must be shown mathematically and be accompanied by a written narrative sufficient to allow the Commission and interested parties to duplicate the calculations. If the derivation is due to a load factor adjustment, application of a percentage, or other adjusting factor, the pipeline must also note or explain the origin of the adjusting factor.

Where workpapers show progressive calculations, any discontinuity between one working paper and another must be explained.