And if any heir of entail, against whom a debt is created for improvements made on the entailed estate to which he succeeds, shall refuse to pay the money required of him under the authority of this Act, and that decrees shall be obtained against him for the whole of the sum or sums of money of which he shall be required to make payment; in every such case the defender shall be liable in full costs of suit; and if decree is not obtained for the full sum or sums of money of which payment has been required, it shall be in the discretion of the court to award costs of suit to either party, as the justice of the case shall direct.