The present invention relates to a method for processing mail pieces to automatically associate a manually entered postage to a class of service and to a system which implements the method. The method includes receiving a postage amount that is to be applied to the mail pieces and searching stored rate tables for one or more classes of service having a postage rate that matches the entered postage amount. The matching classes of service are displayed and the user selects one of the classes of service. The entered postage amount is applied to the mail pieces and transaction information for each is stored. A corresponding weight for each of the matching classes of service may also be displayed to the user. Mail pieces may be processed individually or in a batch using the discussed method and system.