The Secretary may: classify positions in a unit when, in the Secretary's judgment, it is necessary to preserve the integrity of the classification system; and order the head of a principal unit to: take appropriate action to properly classify a position or take other appropriate action to comply with a position classification audit; or modify the unit's classification practices to comply with the findings of an operational audit. The Secretary shall determine the effective dates for newly created or modified classes, position classification plans, and classification standards and procedures. The Secretary shall adopt regulations to provide for effective dates of position reclassifications.