Sections 7501-7505 of this title shall extend to an action upon a bond or specialty in a penal sum with condition for the payment of money or interest of money by installments or on different days, unless such action is commenced after all the sums, whether for principal or interest, which according to such condition can become payable, have become payable. If the action is commenced after all the sums which, according to such condition, can become payable whether for principal or interest, have become payable, or if the action be upon a bond or specialty in a penal sum with condition for the payment of money in a gross sum, judgment for the plaintiff shall be for the penalty and costs of suit, to be discharged upon the payment of the sum justly due, with interest and costs. The sum justly due shall be found by a jury, or by the court if a jury is waived, or otherwise shall be ascertained as may be agreed by the parties, or ordered by the court.