Since the Authority is performing essential governmental functions, the Authority is not required to pay any taxes or assessments of any kind or nature upon any property required or used by it for its purposes or any rates, fees, rents, receipts, or incomes at any time received by it. The bonds issued by the Authority, their transfer, and the income from the bonds are not taxable income for the purposes of the individual and corporate income tax under Illinois law and shall not be taxed by any political subdivision of this State. For purposes of Section 250 of the Illinois Income Tax Act, the exemption of the income from bonds issued by the Authority shall terminate after all of the bonds have been paid. The amount of such income that shall be added and then subtracted on the Illinois income tax return of a taxpayer, pursuant to Section 203 of the Illinois Income Tax Act, from federal adjusted gross income or federal taxable income in computing Illinois base income shall be the interest net of any bond premium amortization.