Turbo Tax did not input negative number for SSA 1099 on Form 1040? Can I manually add this?

I received a SSA 1099 that has a negative number due to me not receiving benefits and paying an overpayment.

I did get SSDI and SSI for a few years, but I never worked until recently.  I did not file a tax return for these years because I never had enough income in SSI or SSDI. Therefore, these benefits were never subject to tax.

I just finished using turbo tax, I have paid but I not filed anything yet. When it asked me to review my documents for errors, I took a look over everything and I noticed line 6a and 6b on 1040 were blank.  In the instructions for my SSA 1099, it says if my benefits are not taxable, but I must otherwise file a return, I should put the amount on line 6a and put a "0" for line 6b for form 1040.

I did input the negative amount for the social security payments section when turbo tax was interviewing me, it did give me warning to review it saying while a negative amount is valid, I should check it over. 

Any ideas why this number did not get added to line 6a and why there is no 0 for 6b? Is it because it is not taxable? If it isn't taxable do I need to worry about it being there? Can I edit this manually or is there something I'm missing to add it in?