Thank you for sharing your token.
The difference that you're seeing is because Montana uses a graduated tax rate rather than applying a single, flat rate to all of your income. While your income does put you in the 5.9% tax bracket, not all of your income is taxed at that rate.
The first $41,000 is taxed at 4.7%, the rest of it is taxed at 5.9%. This creates a blended, or effective, rate that's lower than the 5.9%.
