If you have a lower taxable income, especially if you have kids, you may get an Earned Income Credit (EIC). In order to get this, you must have income. If your deductions are too high, your refund can actually go down. If you have significant W2 income, then this shouldn't matter. To test, enter your W2 information first, then do your schedule C. Your refund or taxes due should improve when you add expenses like mileage and fees. If it doesn't, if they worsen, your deductions are too high. I was adding my business info first and each expense I added was lowering my refund. A tax expert explained it to me. I'm not sure if I explained it as well as he did.