For purposes of D.C. Official Code § 47-2001(p)(2), the term "sales price" shall not include a charge for a nontaxable service that is made in connection with a sale of a taxable communication service, even if the nontaxable charges are aggregated with and not separately stated from the taxable charges for communication services, if the vendor can reasonably identify charges not subject to tax from its books and records that are kept in the regular course of business.
D.C. Mun. Regs. r. 9-493