Wages calculation for QBI

I have reported payroll W2 wages in TT business. In the end, TT Business gives me an opportunity to adjust wages for Section 199 (QBI). 

 

Question:

- Should i leave the TT recommended W2 wages for QBI

- Should I add my personal 401k contribution to W2 wages and report that?

- Is there anything else that i can add to W2 wages

 

As per my understanding, there are 3 calculation methods available, but the differences between them are not clear. Can somebody give an example of three methods (unmodified box method, modified box method etc.) using a sample W2? Which is the preferred method? 

 

Until last year, i left the wages to be the same as what TT business recommended with no adjustments. 

 

Thanks


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