Retirement tax questions

DMERTZ : That was not my contribution nor income but the previous persons info. I was simply acknowledging the exact same experience. 

Noted as to the Solo 401k contributions not being a business expense. However can you explain why when walking through step by step in Turbo Tax and entering Solo 401k plan contributions, exactly as you have indicated; the QBI deduction goes down and there is NO reduction in tax liability in the TT counter at the top of the program?