Delinquency fee calculation for the invoices cleared by credit memo or write off

 Hi,

We are calculating fees only for the invoices which were paid late. It appears that when an invoice is cleared by the write off or credit memo, system is generating fees for the invoice. Please explain us is there any option to exclude the invoices from late fee charge if it is cleared by write off (stand alone or automatic) or credit memo. We know that we can change apply finance charge of the invoice to "N" in order to exclude.

Please guide me if there are any other possible ways for this case.

Thanks.