1. A method comprising: providing a customer with a postage meter device; loading the postage meter with postage credits before charging the customer for the value of the postage credits, printing indicia on one or more items to be mailed using the postage meter; monitoring information provided by a postal service for data associated with each of the one or more items; determining from the data a descending register value associated with each of the one or more items; identifying a first smallest descending register value appearing in the data during a time; identifying a second smallest descending register value, the second smallest descending register value being the smallest descending register value appearing in the data during a previous time period; subtracting the first smallest descending register value from the second smallest descending register value; adjusting the result if the postage meter was refilled during the time period; based upon the result, determining a value of postage associated with the one or more items that is a value of postage actually used by the customer; and charging the customer for the determined value of postage.