Subscription Usage base charge- save the detailed transactions for usage calculation

Summary:

We need to save the customer detailed usage transaction and according to this information, calculate the usage to be charged on the billing line

Content (please ensure you mask any confidential information):

We have a usage based charge product. The usage calculation is complex, we do not get a usage figure from our 3rd party application- but rather we get all detailed transactions for all the detailed usage (date, qty) . According to this, we will calculate the sum of usage and update the usage quantity in the billing line.

My Question- where can we store all these detailed usage transaction in Oracle? Is there ant designated place in the Subscription module?