I am not able to find exact API where product configuration can be managed in account level for billing purpose. This is more specific to product provisioning for billing ( not for CRM) where billing account is considered separate logical entity and need to be associated with resource and service for selected product. So far I have seen TMF666 as only option with extension of TMF666. If some one has concrete reference of another API which I am missing please help.
As far as I understand, according to TMF "orthodoxy", the product configuration is expressed in the inventory (TMF637), and any software system that needs this information could take it on-demand using this API. And if the billing system "wanted" to be provisioned up-front, it would accept a product order (TMF622) that contains the configured product.
The configured product includes product prices that are mapped into paying billing accounts (TMF666). So you have the mapping that way, from Product to Billing Account. I don't think you need to extend TMF666 to create the reverse mapping.
We could of course discuss if there should be a case for having a Billing (or Charging, or any other system) -oriented/optimized view of the data, which takes us into the territory of data replication (see my thread on that here https://engage.tmforum.org/discussion/strategies-for-data-replication).
Hope it helps.
Thanks for suggestion. And I agree to use TMF 622 since billing provision is part of product order. Extension of using TMF666 promote reverse mapping.