By Business First of Columbus sought in July 2008, the last time it submitted a rate plan to the PUCO. The commission eventually approved increases that were roughly half of what AEP had requested, including hikes that were capped at 7 percent for 2009, 6 percent last year and 6 percent for 2011 for AEP Ohioâ¿¿s Columbus Southern Power Co. subsidiary that serves Central and southern Ohio. The PUCO determined in January that those rates contributed to an excessive profit for Columbus Southern in 2009. The commission ordered the company to refund $26.6 million to its customers. AEP also is seeking approval to redesign its generation rate structure so itâ¿¿s more line with prices in todayâ¿¿s market, said AEP Ohio President Joe Hamrock. The companyâ¿¿s current rates are still based on some costs from the early 1990s, he said. If approved by the PUCO, the redesign could result in generation rates lowered by as much as 20 percent over the planâ¿¿s 29 months for some commercial customers and schools that have historically subsidized below-market rates for residential and certain industrial customers, Hamrock said. On the other hand, some industrial customers could see their generation rates climb as much as 10 percent through May 2014, Hamrock said.