I have this same question, and a possible answer, but I'm not at all sure. I have nothing on Schedule 1, but I do have an entry on line 6, as do you. The amount is the exact same as a cash contribution I made to charity. (See 1040 line 10b)
Could that be it? Do you have an entry on 1040 line 10b, and if so, is that what is on line 6 of the worksheet?
Apparently, if you take standard deduction (no schedule A) but gave cash to charity, you get a deduction on the 1040.
It doesn't make sense that nothing shows on Schedule 1, though... but this is the only link I can see.
You are correct. The 1040 Line 10B charitable donation adjustment to income is being added to the amount from Sch 1 to equal your Line 6 adjustments on the Social Security worksheet. This is a new adjustment to income in 2020 for non-itemizers. For 2021, that amount will jump to $600 if married filing jointly.
I do have the exact same situation as you described. I also guessed the $300 is the allowable ceiling on the charitable contribution, which is an adjustment to income. So, I filed as it stood.
Yes, $300 is the allowable ceiling on the charitable contribution, which is an adjustment to income for 2020.