I assume from your question you are interested in records regarding Defined Cost. Under ECC Option C the Contractor is required to keep records of Defined Cost as set out in 52.2 which include accounts of payment, records of payment, communication about and assessments of CEs and also any other information set out in the Works Info. This last bullet point allows the Employer to set out for example specific requirements about cost capture, time-sheets and codes of accounts i.e. Work Breakdown Structure, etc.
The Employer could also set out other requirements or constraints in the Works Info in respect of records, such as as built drawings, etc.
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