One of the main functions of a call accounting system is to apply a cost to telephone call records, the tariffs applied should mimic the cost you the customer actually pay to your telecom service provider.

If costs are inaccurate, the purpose of a Call Accounting service is nullified to the extent of the inaccuracy. A Call Accounting system with 97% accuracy is very useful, one that reports total call costs at 65% of the telco invoice is useless.

Some telecom service providers (Telcos) have simple clear and transparent pricing. A simple example may be; all calls to a mobile number are billed per second of talk time (connection time) and the cost per second is openly stated. Some have a different policy, an example being, your telco charges different rates to multiple mobile providers, and your country has implemented "number portability", in other words you do not know on which network the dialed number resides and therefore you do not know the cost of the call.

Some telcos have as few as 10 different call costs dependent on call destination and others have more than 5000 different tariff / destination combinations. Add to this the complication of perhaps 20 different "packages' and "in bundle" minutes to certain destinations, it is obvious that the soup is not clear.

You may ask "How does a call accounting service manage to duplicate this, especially those with an international footprint?"

There are suppliers who offer solutions without cost tables. The customer adds the information on installation and maintains it for the life of the service. This is only practical in a situation where call tariffs a very simple and where your implementation budget restricts you to self service. Even then, the work is tedious and time consuming, it is after all a specialist job. If your call tariffs are complex, duplicating them is a minefield and should be left to the experts.

Other suppliers offer a full and complete call tariff package with a service level agreement to be within X% of the telco account or will justify the differences. These services are always offered at a premium price as the work and commitment on the suppliers behalf is not trivial.

It has to said that telco billing has errors, Aberdeen Group reported that at least 12% of all telco billing contained errors in favor of the Telco (suprise!) , so if your Call Accounting system does not match your telco invoice, approach your supplier to identify where the differences are, once the reasons are identified you may be in a position to challenge your telco provider.