Rules 25-4.053-25-4.056, F.A.C., generally address rate-grouping plans for LECs. Under the rate-base, rate-of-return form of regulation, LECs often had plans and pricing structures (rates) that were “grouped” based on the number of access lines a subscriber could call. The number of access lines in the local calling area of an exchange was referred to as the “calling scope”", and these rules provided guidance for establishing the rate groups using calling scopes. These rules are related to the rules that provide guidelines and requirements for processing requests (Extended Area Service).