Capital outlay notes issued pursuant to this section may be issued for a period greater than the end of the third fiscal year following the fiscal year in which the notes were issued, but not greater than the end of the twelfth fiscal year following the fiscal year in which the notes were issued. Each fiscal year any such notes are outstanding following the fiscal year in which the notes were issued, the local government shall retire principal on the notes in an amount that is estimated to be at least equal to an amortization that will reflect level debt service of the note issue, as established at the time of the sale and as indicated in the resolution authorizing the notes, or as otherwise approved by the comptroller of the treasury or the comptroller's designee; provided, that all such notes shall be retired in no event greater than the twelfth fiscal year following the fiscal year in which the notes were issued. The resolutions authorizing any such issue of notes shall provide for principal of the notes to be payable annually, either by maturity or by mandatory redemption. The comptroller of the treasury or the comptroller's designee, in approving any such notes, may waive the requirement of periodic retirement. The resolution authorizing such issue of notes may provide that the notes shall be subject to redemption prior to maturity at the option of the local government. Notes issued pursuant to this section totaling two million dollars ($2,000,000) or less shall be sold at competitive public sale or by the informal bid process described in § 9-21-609. Notes issued pursuant to this section totaling greater than two million dollars ($2,000,000) shall be sold at competitive sale.