The inventive system allows for more efficient use of resources for providing location information in a wireless network where multiple sources of such information may be available. In one implementation, a first source of location information such as Cell ID information is used to monitor the location of a mobile unit. The first source may provide sufficient location information in many instances. For example, in the case of a location-based billing application, Cell ID information may be sufficient in some cases to indicate that a subscriber is within or outside of a home zone. In other cases, more accurate information may be required to make such a determination. When required, a more accurate source of information such as TDOA or GPS information may be invoked. The invention allows for more efficient use of the multiple sources by allowing for reduction of the instances where a high resource location information source is accessed.