After the hour fixed for the filing of objections, the court shall proceed to hear and determine the matter of making an assessment to raise a fund for the payment of the preliminary costs and expenses. The court will determine from proof offered the amount necessary to cover the cost and expenses, and if the court is of the opinion that it is not expedient to make an assessment for such purposes, the court will so decree; but if the court is of the opinion that it is expedient, the court will make an assessment for the amount determined upon the respective tracts of land in the proposed improvement district, and make the assessment on the basis of acreage.