1. Prior to the issuance of bonds, notes or certificates of indebtedness authorized for the purpose of improvements, any person, firm or corporation owning land upon which a benefit has been assessed for such improvements may pay all or any portion of the benefit so assessed against the land, and, upon such payment, the benefit so assessed shall be discharged to the extent of such payment.
2. No such payment may be made after the issuance of bonds, notes or certificates of indebtedness authorized to be issued in payment of such improvements except as provided by the district.