(2) Whenever it appears to the appraisers that the benefits to all the lands within the subdistrict will be less in value than the cost of the proposed works, the appraisers shall file a preliminary report of their work with the board of directors and recommend to the board that the engineering plan be amended so that the proposed works can be constructed at a cost less than the benefits to be derived therefrom. If the board obtains an amended engineering plan, the appraisers shall proceed with their work.
(3) Upon completing their work, the appraisers shall file a final report with the court and certify that the appraisal has been completed and that there is nothing further for them to do in regard to the matter.