=item creditbillpkgnum - primary key
-=item creditbillnum - Credit application to the overall invoice (see L<FS::cust_credit::bill>)
+=item creditbillnum - Credit application to the overall invoice (see L<FS::cust_credit_bill>)
=item billpkgnum - Line item to which credit is applied (see L<FS::cust_bill_pkg>)