Software is a wonderful tool but the person signing the return should still rely on the smell test. Without numbers we don’t know what happened here, but we do know that California tax rates are generally higher than Arizona tax rates, and that unlike most states, California gives Arizona residents a credit for taxes paid on nonresident income.

So, let’s say a Zonie makes $10,000 in California and it’s taxed at a 5% rate. The same income is taxed at 2% by Arizona. You would expect California tax before credit to be $500; the Arizona credit to be $200; and the balance owed to California to be $300.

If that’s not the answer that the software comes up with, then figure out why it doesn’t smell right.