(1) Whenever any assessment roll for local improvements shall have been confirmed by the district board of commissioners, the regularity, validity, and correctness of the proceedings relating to the improvements, and to the assessment therefor, including the action of the district commissioners upon the assessment roll and the confirmation thereof, shall be conclusive in all things upon all parties, and cannot in any manner be contested or questioned in any proceeding whatsoever by any person not filing written objections to such roll in the manner and within the time provided in this chapter, and not appealing from the action of the commissioners in confirming such assessment roll in the manner and within the time in this chapter provided. No proceedings of any kind shall be commenced or prosecuted for the purpose of defeating or contesting any such assessment, or the sale of property to pay such assessment, or any certificate of delinquency issued therefor, or the foreclosure of any lien issued therefor. However, this section shall not be construed as prohibiting the bringing of injunction proceedings to prevent the sale of any real estate upon the grounds (a) that the property about to be sold does not appear upon the assessment roll, or (b) that the assessment had been paid.
(2) This section also shall not prohibit the correction of clerical errors and errors in the computation of assessments in assessment rolls by the following procedure:
(a) The board of commissioners may file a petition with the superior court of the county wherein the real property is located, asking that the court enter an order correcting such errors and directing that the county treasurer pay a portion or all of the incorrect assessment by the transfer of funds from the district's maintenance fund, if such relief be necessary.
(b) Upon the filing of the petition, the court shall set a date for hearing and upon the hearing may enter an order as provided in (a) of this subsection. However, neither the correcting order nor the corrected assessment roll shall result in an increased assessment to the property owner.