Oh, if anyone else finds this answer - to get to the calculations for QBI, you need to look for the "SMART WORKSHEET FOR: Schedule C ([your business activity]): Profit of Loss from Business". There is another worksheet earlier in the document that doesn't explain how the lower-than-expected number for QBI was calculated. Bottom line is they deduct your self-employment health insurance premiums and half of self-employment tax from your net profit to get the QBI base. It's confusing, and I think the IRS regs aren't at all clear that this is the right way to do it, so some of us may be filing amended returns in the future.
