Regular and additional or nonroutine examinations conducted by the Administrative Director pursuant to Section 4600.6(q) of the Code will ordinarily be commenced on an unannounced basis. To the extent feasible, deficiencies noted will be called to the attention of the responsible officers of the company under examination during the course of the examination, and in that event the company should take the corrective action indicated. When deemed appropriate, the company will be advised by letter of the deficiencies noted upon the examination. If the deficiency letter requires a report from the organization, such report must be furnished within 15 days or such additional time as may be allowed.