An approved shared work compensation plan in effect may be modified with the approval of the commissioner. If the hours of work are increased or decreased beyond the level in the original plan, or any other condition is changed, the employer shall promptly notify the commissioner. If the changes meet the requirements for approval of a plan, the commissioner shall approve the modifications. This approval shall not change the expiration date of the original plan. If the modifications do not meet the requirements for approval, the commissioner shall revoke the plan as specified in RCW 50.60.060.