Entry in this field depends on the Finance Charge Type specified for the customer (in AR Customers).
If the finance charge type is “A-Account”, enter '1' or 'New'.
If the finance charge type is “Invoice”, enter the line number of the original invoice to which you are applying this finance/service charge.
If the finance charge type is "RecType", press Ctrl+A, select, or click the Create FC Detail button. The system automatically locates all invoices posted to the receivable type that meet the Due Date Cutoff and Paid Date Cutoff criteria, and calculates finance charges as applicable.