Other professionals, for example personal injury lawyers, charge based on results. In other words, standard billing rates measure the standard revenue, or opportunity cost, of performing work. Setting a standard billing rate is a management decision. Setting price is a marketing decision. If a value for your service is less than the cost, clients will not complain about your bill.
Clients accept value billing better than PR professionals do.
It did not matter who did the work. The value billing rate was used. Think about charging a premium for strategic or tactical counsel. Always discuss price before you perform a service. You lose leverage otherwise.