The state Public Service Commission has approved a rate change effecting Ameren Missouri customers. The company filed for an adjustment to their Fuel and Purchased Power Charge, or FAC, to reflect actual costs from February through May of this year. The adjusted rates will actually produce a price drop for customers beginning September 25th. Residential customers using just over 1,000 kilowatt-hours a month will see their bills drop by approximately 96-cents. Ameren Missouri provides electric service to more than one and a quarter million customers in Missouri.