Based on your business scenario, please use either of the following TCode for Billing Copying Control to check your pricing type:
VTFA - For
VTFL - For Delivery related billing
VTFF - For Billing to Billing reference
Preferably, the pricing type should be either C - Copy manual pricing elements and redetermine the others or G - Copy pricing elements unchanged and redetermine taxes. For further details on pricing type, please search with search term "SAP SD Pricing Type".
In addition to that please check your pricing analysis for billing thoroughly to understand the root cause of automatic pricing error at billing level.
If you still face any specific concern or query, do revert back with it.
Cheers, JP