The State shall pay interest on late payments as defined in Regulation .01 of this chapter at the rate of 9 percent per annum if: The vendor submits an invoice for the late payment interest within 30 days after the date of the State’s payment of the amount on which the interest accrued; and A contract claim has not been filed under State Finance and Procurement Article, Title 15, Subtitle 2, Annotated Code of Maryland. The State is not liable for interest: Accruing more than one year after the 31st day after the agency receives the proper invoice; or On any amount representing unpaid interest.