In Turbotax Home & Business, I have a schedule C business. This year that business posted a $1500 LOSS. When the software gets to the question regarding whether the business is a QBI (it meets the definition), and I say yes, my Federal Tax Due goes from $421 to $587. If I answer no to the question, it stays at $421 owed. That makes it appear as if it is disallowing 20% of my loss. Can anyone explain this?