Notwithstanding any other provisions of this chapter, a local legislative body may use, pledge, or otherwise obligate its general funds for payment or security for payment of tax allocation bonds issued or incurred under this chapter but only if those general funds are derived from a designated tax allocation district and used for payment or security for payment of tax allocation bonds issued or incurred under this chapter for redevelopment of that district and only to the extent that positive tax increments or lease or other contract payments in that district's special fund are insufficient at any time to pay principal and interest due on such bonds.