What assessment procedure is designed to work with and complement the assessment procedures to contribute to the grounds for confidence in the effectiveness of the security controls employed in the in

Extended assessment procedures are specialized, more in-depth assessment techniques that build upon basic assessment procedures to provide additional evidence and higher assurance regarding the effectiveness of security controls. They are used to address specific high-impact controls, unique system characteristics, or areas requiring greater scrutiny, thus complementing and strengthening the overall assessment.

'Subordinate' procedures would imply a lower level or less comprehensive assessment, which does not fit the description of contributing to increased confidence in effectiveness.

'Based' is too vague and does not describe a type of assessment procedure designed to complement others.

'Cross control' could refer to dependencies between controls but is not a standard term for a complementary assessment procedure in this context.