At the time and place fixed for the hearing of protests or at any time to which the hearing is adjourned, the city council shall hear the evidence introduced in support of the protests. At the hearing the city council may modify the provisions for the maintenance and operation as stated in the resolution of intention by omitting one or more of the items stated therein, and may modify the boundaries of the district, but any land not within the district as described in the resolution of intention may not be included therein. The city council may change the percentage of the total maintenance and operation cost to be paid by the city and by the district; but the percentage to be paid by the district shall not be increased without further notice being given and a hearing being held in the same manner as notice was given and a hearing held on the original resolution of intention.