Increase elderly homeowner and renter income tax credit

This bill increases the maximum income tax credit available to elderly homeowners and renters in Montana by adjusting the credit calculation thresholds and amounts. It directly affects seniors who own or rent their primary residences by providing a tax credit that offsets a portion of their property taxes or rent-equivalent costs. The key mechanism involves raising the income threshold at which the credit begins to phase out and increasing the maximum credit amount, while also updating the definition of household income to $14,100 for calculation purposes. The bill includes an inflationary adjustment provision to ensure the credit maximum and phase-out income levels keep pace with economic changes.