Mont. Code Ann. § 25-10-104
25-10-104 When costs of appeal discretionary
25-10-104 . When costs of appeal discretionary. (1) In the following cases, the costs of appeal are in the discretion of the court:
(a) when a new trial is ordered;
(b) when a judgment is modified.
(2) In all other cases, the successful party shall recover from the other party the successful party's costs.