On the Social Security Benefits Worksheet the amount from Form 1040 Line 8 is entered on the Worksheet Line 3.
The Form 1040 Line 8 amount is from Schedule 1 Line 10 which is the total of Lines 1 thru 7 and 9 of Schedule 1. Line 3 of Schedule 1 is the amount of self-employment business income or (loss) from Schedule C.
Self-employment income or loss is required to be entered on the Social Security Benefits worksheet.
Go to IRS Form 1040 Instructions on page 31 for the Social Security Benefits Worksheet - https://www.irs.gov/pub/irs-pdf/i1040gi.pdf#page=31
IRS Form 1040 Schedule 1 - https://www.irs.gov/pub/irs-pdf/f1040s1.pdf
