401K solo tax reduction numbers are too low

Hi,

 

I have a small individual LLC business, and opened individual 401K account.

By entering different numbers in TurboTax self-employed 401K form I can see the different federal taxes calculated. 
By lowering Elective Deferrals by $1000, I get tax increase of $182.

By lowering my business income in another TT form by $1000, I get tax decreased by $314.

 

I would expect the numbers to be close, if not the same.

 

Am I doing something wrong?

 

thank you!