(2) The revenues apportioned to the funds pledged to the payment of bonds and obligations shall be separately held and kept and accounted for. The corporation shall disburse the funds only for the purposes for which levied until the indebtedness and obligation for which the assessment was made is fully paid with interest, whereupon the remainder shall be transferred to the general fund of the corporation for the payment of expenses of the corporation and its operation and maintenance. At the time of making assessments the board of directors shall first determine the estimated amount necessary for the expenses of operation and maintenance and then the several amounts for the respective funds, and determine that the whole amount thereof is within the limitations, restrictions and provisions of the landowners’ notice provided for in ORS 554.170 to 554.190. [Amended by 1969 c.694 §47; 2001 c.215 §30]