To help with prepaid / postpaid you can check the category key.
For Prepaid there will be an OICK (old and reflects pre-CAMEL solution) or a CAMEL Subscription Identity (CSI) flag set against the MSISDN. This will be the CSP – CAMEL Service Profile.
STYPES can be used with a value for CDRs. In the past I have used STYPE with a value to help with
prepaid and postpaid CDR processing. Mediation device can have logic to filter / process CDRs using a STYPE value.