Summary assessment scope: limited inspections apply; detailed scrutiny needs Category I classification and higher assessed income. IACs should inspect an approximate number of summary and scrutiny assessments per summary-assessment circle by limited, non-detailed checks using the Board's prescribed tests, with Commissioners empowered to modify the suggested inspection numbers. A specified case may be taken for detailed scrutiny only if it is designated Category I and the returned or assessed income in the current or either of the two preceding years exceeds the prescribed income threshold; otherwise it is to be processed by summary assessment.