The audit methods relevant to the certification audit shall be defined in the audit strategy provided for in Article 6(2).

To achieve the audit objectives and to provide the opinion as set out in Article 9(1) of Regulation (EU) No 1306/2013, the audit steps shall include systems audits, substantive testing, and the verification of reconciliations on financial and management declarations.

Substantive testing of expenditure shall cover the verification of legality and regularity of the underlying transactions at the level of the final beneficiaries. For those purposes, the certification body may accompany the paying agency when it carries out secondary level on-the-spot checks. The certification body may not accompany the paying agency when it carries out initial on-the-spot checks, with the exception of those situations, where it would be physically impossible to re-verify the initial check carried out by the paying agency. As regards substantive testing, the certification bodies may use an integrated sampling approach.

The Commission shall provide further conditions and guidance on designing the audit procedures, sampling integration, planning and carrying out the on-the-spot re-verification of transactions through the guidelines as referred to in Article 6(4).