Do you have to make manual adjustments to the service/invoice dates whenever a user doesn’t pay his invoice right away? This addon module will enable you to skip all that, because the Fix due date addon module automatically detects those situations and fixes the dates, not only for the service/domain but for the invoices also!
If some user pays the invoice a few days late, why should he have those few days stripped away from him and why should you have to manually correct the dates on the service details page and make adjustments to the invoice?
Using the Fixed due dates module makes your life much easier as it also detects suspended accounts! Now, if the service is suspended and a payment is a few days late, user gets his service reactivated with a new date, synchronized to the payment date and the invoice with the corrected dates!