Get ready to fork over more cash on your monthly electric bill. The Missouri Public Service Commission approved a rate hike for KCP&L on Wednesday that will cost residential customers an average of $12.82 a month starting in September.The total increase will be about $95 million for KCP&L.And another rate increase may be on the way. The concurring opinion written by the commission's chairman, Robert M. Clayton III, says:Rate payers should be aware that these increases are not the last in