Cost accounting records requirement mandates telecom companies to maintain detailed activity-wise cost records and reconciliations, including interconnection and related party disclosures. Companies engaged in specified telecommunication activities must keep detailed cost accounting records, in the formats and Proformae prescribed by the Schedule, enabling computation of activity-wise costs from materials, labour and other cost elements; records must be completed within ninety days after year end, permit cost control and auditor reporting, require reconciliation with financial accounts, and non-compliance attracts penalties under the Companies Act.