On 2106 line 9, column b, how does TurboTax calculate that?

On 2106 question 9, column b, how does TurboTax calculate that?

 

Last year, I had $1755 in line 8 column b.

Then, TurboTax calculated $1404 in line 9, column b. 

 

I read the instructions, and I don't get how they arrived at that. I thought it should be 50% of line 8. What did I entered for it to be calculated that way?