Systems and methods are disclosed for performing Policy and Charging Control (PCC) for packet core networks. One embodiment comprises a PCC architecture that includes an online charging system (OCS). The OCS receives a request for charging rules for an initial data service from a PCRF. The request from the PCRF includes a service indicator for the initial data service. The OCS selects a charging method for the initial data service based on the service indicator, and transmits a response to the PCRF that includes the selected charging method. The PCRF may then make a PCC decision based on the charging method selected by the OCS, and a PCEF may enforce PCC rules for the initial data service. If there is a service changing during a data session, the OCS selects a charging method for the new data service, and the PCRF updates the PCC rules accordingly.