Mont. Code Ann. § 17-8-312
Charges for services or supplies among agencies -- valid claim
17-8-312 . Charges for services or supplies among agencies -- valid claim. (1) Subject to 17-8-242 , charges for services and supplies incurred between state agencies are considered a debt that must be paid by the receiving agency as if the amount were owed to a vendor outside of state government.
(2) Agencies shall use all funds at their disposal to pay the bills for specific charges for services or supplies provided by another state agency.