Okay!
I do appreciate obtaining ECR from the contractor. With these procedures, we can confirm that they made the payment to a particular employee. However, for example, if the contractor has 10,000 or more employees (like G4S or ISS) all over India, their PF contribution is from one location (e.g., Gurgaon or Patna), and only 3 employees are working with you (for instance, in Chennai), then I think ECR collection (which contains the details of 10,000+ employees) will be an unnecessary time-consuming task.
During Statutory Audit, only physical documentation is valid, such as a screenshot of "IP Mapping" in ESI and "Para 36B Proforma" for PF along with paid challans. Self-developed Excel sheets may be useful for tracking, but they cannot be considered a statutory document.
Please correct me if I'm wrong.