Notwithstanding the provisions of Section 8117, upon the completion of the surveys referred to in Section 8160 and upon recommendation of the engineer or engineers, in which recommendation shall be included the estimate of cost of each proposed improvement, the commission by resolution duly adopted and recorded in its minutes may approve any changes in the location or locations of the projects described by the board of supervisors in its resolution of intention to form the district, as to the commission may appear reasonable and proper under the circumstances. The said resolution shall set forth the reasons for such changes or additions and the cost of each project as recommended in the engineer’s report.