The hearing on the proposed assessment shall be held by the board of trustees or the administrator sitting as a board of adjustment and equalization at the time and place specified in such notice and not less than twenty days nor more than thirty days after the date of the first publication, unless such session be adjourned, with provisions for proper notice of such adjournment. At such meeting, the proposed assessments shall be adjusted and equalized with reference to benefits resulting from the improvement and shall not exceed such benefits.