Yes - you are still required to file your quarterly IFTA report even if you didn't operate outside your jurisdiction for a given quarter.
New decals will be supplied to your fleet whenever you renew your IFTA license annually. If you need replacement or additional decals during the year they can be ordered from your jurisdiction.
For one-time trips between two or more jurisdictions fleets can use temporary trip/fuel permits. These are only valid for one specific trip and must be ordered for each state that is being traveled through. The duration and cost of the permits differ from state to state.
Late payments are subject to a penalty of $50 or 10% of the total tax due, whichever is higher. Interest is charged on payments received after the tax report's due date and is computed on the amount of tax due by each jurisdiction.