There is not currently a linkage between credits/payments on the cash register report to it's corresponding biblio/item.
The biblio information is only linked to the charges.
We use the cash register report daily at our library and it would be very helpful to have the item barcode and biblio title attached to the credits, writeoffs, etc. In order to track that info down you need to perform 4 or 5 extra steps-- click on the patron's barcode, search through their fines account, locate the fine/credit, etc. Since that info is captured for the fines (items marked lost) it should be there for the credit/writeoffs too.