A method of operating a charging system (22) for a telecommunications network comprises: (1) receiving a charging request in conjunction with a telecommunications activity involving a telecommunications terminal; (2) determining a default account to which a charge resulting from the charging request may be allocated; (3) making a request for an externally-controlled account selection of a selected account; and, (4) finally allocating the charge to the selected account. In an example embodiment and mode the method further comprises, prior to making the request for the externally-controlled account selection of the selected account, making a temporary allocation for a reservation for the telecommunications activity; and performing a default account rating for the telecommunications activity, the default account rating being performed upon assumption of use of the default account.