Not many Markets have deployed CAMEL Phase 4.0. CAP V4 is the last major work that has been done with the CAMEL standard. You can link CAMEL with AOC type Services. For Realtime Display of Balance (before, during and after a session) it is better to use Diameter. It is geared up for MSCC bundles.
For Media/VoLTE/ViLTE/etc.., SIP/Diameter is now the way forward.
VBR/ Wallis Dudhnath