For the purpose of compensating a communications services provider holding a certificate of registration under § 58.1-653 for accounting for and remitting the tax levied by this chapter, a communications services provider shall be allowed the following percentages of the first 3% of the tax levied by § 58.1-648 and accounted for in the form of a deduction in submitting his return and paying the amount due by him if the amount due was not delinquent at the time of payment. The discount allowed by this section shall be computed according to the schedule provided, regardless of the number of certificates of registration held by a communications services provider.