Whenever a defendant is sentenced to pay a fine or costs under 46-18-231 or 46-18-232, the court may grant permission for payment to be made within a specified period of time or in specified installments. If no such permission is included in the sentence, the payment is due immediately.
When Payment Of Fine Or Costs Due
Mont. Code Ann. § 46-18-234, under Form of Sentence.
Mont. Code Ann. § 46-18-234