1. Service Address. Payments by a customer for cellular telephone service from telephones without a fixed location shall be allocated among taxing jurisdictions to the location of the customer’s principal service address during the period for which the tax applies.

2. Presumption. There is a presumption that the service address a customer supplies to the taxpayer is current and accurate, unless the taxpayer has actual knowledge to the contrary.

3. Roaming. When the cellular telephone service is provided while a subscriber is roaming outside the subscriber’s normal cellular network area, the gross income shall be assigned consistent with the taxpayer’s accounting system to the location of the originating cell site of the call, or to the location of the main cellular switching office that switched the call.