Within thirty days from the expiration of the time for filing complaints as provided for in the next preceding section hereof the board of directors shall fix a time and place within the county in which the property of complainants is located, for the purpose of hearing such complaints. At least five days’ notice of such meeting shall be given to all complainants whose property is located within the county. The board of directors shall hear and determine all matters relative to said complaints, keep a record thereof, and report their findings to the county clerk of the county in which such meeting is held, and such findings shall become an amendment of the report of the benefits assessment commission provided for in section 64* hereof.