At the time appointed for hearing objections to such assessment roll, the board shall consider the engineer’s report and the assessment roll and shall hear and determine all objections which have been filed by any owner of property, or his agent, to the regularity of the proceedings in making such assessment, to the correctness of such assessment, to the amount levied on any particular lot or parcel of land, including the benefits accruing thereon and the proper proportionate share of the total cost of the improvements to be borne thereby and to the inclusion of any lot or parcel of land in the proposed district. The board shall have the power: to adjourn such hearing from time to time and, in its discretion, to revise, correct, conform or set aside any assessment and to order that such assessment be made de novo; and to exclude any lot or parcel of land from an assessment roll which, in the judgment of the board, it finds will not be benefited by improvements to be made. If any assessments are increased in an amount greater than twenty percent (20%) of the amount of the assessments as set out in the notice of the hearing, then a new notice of the hearing shall be given and a new hearing held as aforesaid. No new hearing shall be required in the event that any assessments are decreased in any amount or are increased in an amount up to twenty percent (20%) of the original amount.