Where is dunning letter amount of the transaction dunning history saved

We have an audit requirement to provide historic information for all dunning letters. We could find almost all the required field in the DB level however we cannot find the amount which was there at the time of the letter generation.

Need to know the table and column name where is the transaction amount amount saved for the historical dunning letters.

We can see on the screen while navigating to "Dunning History" button for a specific transaction and we can see what was the remaining amount for each letter which was generated. Need to know where this data is saved to do data extracts for reporting purposes.