AU 319.107

Although the inverse relationship between control risk and detection risk may permit the auditor to change the nature or the timing of substantive tests or limit their extent, ordinarily the assessed level of control risk cannot be sufficiently low to eliminate the need to perform any substantive tests to restrict detection risk for all of the assertions relevant to significant account balances or transaction classes. Consequently, regardless of the assessed level of control risk, the auditor should perform substantive tests for significant account balances and transaction classes.