My 2020 Partnership K-1 show a total income figure on Line 1. I will make it up - $200,000. That is all self employment income from the partnership. The K-1 Statement A for the QBI is reduced by Health Insurance and 401(k) contributions so Statement A says QBI is $200,000 - $20,000 (401k) - $20,000 (health insurance) = $160,000. The problem is the TurboTax program automatically reduces the Statement A QBI figure a second time for 401k contribution - and it uses the wrong amount because it is calculating a percentage of 160,000/200,000 = 80% and reducing the $160,000 by 80% of the 401k instead of 100%. Applies the same 80% to the 1/2 self employment tax reduction so it is wrong too. And before you say just use the Line 1 number instead of the Statement A number, there is no place to reduce the Line 1 number by the health insurance premiums so percentage errors still exist and then filing will not match K-1.
