The program reduces QBI by 1/2 SE tax deduction and SE pension only by the amount that SE Income is included in QBI. For example, let's say there in a K-1 with $100,000 of ordinary income, $50,000 of guartenteed payments, $150,000 of SE income on line 14 and $100,000 of QBI. This would result in a 1/2 SE tax deduction on Schedule 1, line 27 of $6,870. However, guaranteed payments are not included in QBI. Therefore, the program only uses $100,000 of SE income as allocable to QBI. 100,000 / 150,000 * 6,870 = 4,580. The program reduces QBI by $4,580 and will reduce QBI for the SE pensions by the same ratio.