A reverse rating system determines the duration for which a phone call or other transaction may continue, given an account balance on a pre-paid customer account. The duration may take into consideration multiple time bands, applicable discounts, rating plans and other characteristics of the customer account and telecommunications service. The telecommunications service provider may employ the duration information to determine when to disconnect an ongoing transaction. As a result, the telecommunications service provider avoids substantial revenue loses from continuing to allow a pre-paid customer to continue their transaction longer than their account balance will support.