No provider shall charge a rate for Collect Calling in excess of $0.25 per minute, or a rate for Debit Calling, Prepaid Calling, or Prepaid Collect Calling in excess of $0.21 per minute. A Provider's rates shall be considered consistent with this section if the total charge for a 15-minute call, including any per-call or per-connection charges, does not exceed $3.75 for a 15-minute call using Collect Calling, or $3.15 for a 15-minute call using Debit Calling, Prepaid Calling, or Prepaid Collect Calling.