On and after August 14, 2009 (the effective date of Public Act 96-533), any electric utility providing rate relief pursuant to Section 16-111.5A of this Act shall not deem any residential or non-residential customer to be ineligible to receive that relief solely based upon that customer’s purchase of electricity from a supplier other than that electric utility at the time the rate relief is to be credited to that customer. Nothing in this Section shall entitle customers of an electric utility that had been previously deemed ineligible prior to August 14, 2009 (the effective date of Public Act 96-533) to become eligible for rate relief credits.