Any person, firm or corporation may, at or prior to the hearing on the apportionment, file objections in writing against the validity of the assessment roll or amount of the proposed assessment, specifically setting forth the nature thereof, and shall have full opportunity to be heard thereon. The governing body shall adjudicate and determine the objections and may make such order as may be just and proper. Any objections to the regularity of the proceedings with reference to the making of the improvement or the validity or the amount of any assessment shall be deemed waived unless presented at the time and in the manner herein specified. At the hearing on the apportionment, or any adjournment thereof, the municipal governing body may review and correct the apportionment and assessment, and raise or lower the same as to any lots or tracts of land, as it shall deem just. The governing body by resolution shall confirm the apportionment and assessment as so revised and corrected by it.