I think we agree. And to summarize, an IRA adds only $4400 of deduction to the example (because the $5500 IRA deduction reduces the Section 199A deduction by $1100.) And then the tax deferral from using the traditional IRA becomes 12% of $4400, or $528. Which isn’t that much if a taxpayer will pay any of those taxes back when they withdraw. Finally, this taxpayer may not actually be getting any tax benefit from holding the money in the IRA if the growth in value and the qualified dividends aren’t taxed (because they’re taxed at a 0% tax rate).

Second, I actually had a question about an older post on the Section 199A deduction and its affect on retirement planning: http://evergreensmallbusiness.com/sec-199a-changes-retirement-planning/

I am having a hard time inputting the figures you used into excel and seeing a noticeable advantage to not putting money into a traditional versus a taxable/roth account. I wish I could post the image of my spreadsheet but it won’t let me, so I will paste it as a text below. Basically I do not see an advantage in either direction. I show the taxable/roth scenario winning by 0.09%. What am I missing?

Category S1 Roth S2 Trad
Income $100,000.00 $100,000.00
Post Stan. Ded. $76,000.00 $76,000.00
199A Deduction $15,200.00 $14,100.00
Taxable Income $60,800.00 $56,400.00

Traditional Cont. $- $5,500.00
Roth/Taxable Cont. $5,500.00 $-

Effective Tax Rate (mfj) 11.37% 11.32%

Gross Income $100,000.00 $100,000.00
Taxes ($) $6,914.88 $6,386.88
Ret. AC (with. tax adj.) $5,500.00 $4,877.40
HH Cash-Flow $87,585.12 $88,113.12
Total $ $93,085.12 $92,990.52