The corporation will be liable for the payment of interest if the corporation has failed to submit a warrant for payment of a proper invoice to the Department of Taxation and Finance within the 30-day period described in section 801.4(a) of this Part, except when the contract payment is subject to the conditions set forth in section 801.5 of this Part. Any time taken to satisfy any of the conditions set forth in section 801.5 of this Part will extend by an equal period of time the date by which contract payment must be made in order for the corporation to be liable for interest payments. The corporation is not liable for payment of interest with respect to requests for payments of an advance. Furthermore, the corporation is not liable for payment of interest with respect to any payment to a contractor which does not exceed the contractor's current outstanding advance balance. In the event a request for payment submitted by a contractor exceeds the outstanding advance balance of the contractor, any interest due to late payment will be calculated only on the amount of the request for payment which exceeds the advance balance.