When assessing whether the controls are operating effectively, does the auditor need to reperform the control? For

Question:

When assessing whether the controls are operating effectively, does the auditor need to reperform the control? For example, if personnel check the correctness of computations on an invoice and initial the bottom of a document to indicate that the control has been performed, does the auditor need to reperform the procedure? Explain the rationale for your response.