§ 1201-b. Additional credits against taxes administered by cities of one million or more. Any person, corporation or other entity required or permitted to grant rebates or discounts on bills for electricity, gas or steam in accordance with a local law adopted pursuant to Article 2-G of the general city law shall be entitled to a refundable credit for such rebates and discounts made, to the extent such credit is specifically authorized by such article of the general city law, against the amount of tax of be paid pursuant to any gross receipts tax imposed by a local law adopted pursuant to subdivision (a) of section twelve hundred one of this chapter. Notwithstanding any other provision of law to the contrary, no taxpayer taking a credit as authorized herein shall incur any increased liability for any taxes imposed pursuant to the authorization contained in chapter seven hundred seventy-two of the laws of nineteen hundred sixty-six, as amended, by reason of such credit.