In case there are sufficient funds on hand in such district, or there are unpaid assessments outstanding or other property belonging to such district in an amount sufficient to pay such expense, the expense of abandonment and dissolution shall be paid out of such funds or out of funds realized by the sale of such property. Where such district is free of indebtedness but there are not sufficient funds on hand or unpaid assessments outstanding or other assets to pay such expense the board shall assess such expense against the property in the district in the same proportions as the last preceding assessments of benefits. Any excess remaining to the credit of such district after sale of its assets and after payment of such expenses shall be prorated back to the property owners in the district in the proportions according to class and benefits as last assessed. If the petition is denied, the costs of said proceedings shall be paid by the petitioning owners.