+1 to Turbo Tax doing this calculation. "Hey we'll do your taxes for you... by the way do you want to do an entire tax return by hand as sub-step of that?" Ick!

Also this answer *sort of* helps, but how can I guess whether I'm going to save money by doing this calculation? I still don't get it.

What amount is considered a large refund to do the recompute?

My guess is that if you meet all the requirements, (had a refund, paid AMT, itemized deductions, etc.) then you will get some benefit from re-doing last years taxes to exclude some of your refund from this year's taxes.  My even more nebulous guess is that if your last year's AMT tax amount is, say, twice the amount of your refund, then you likely can exclude all of last year's refund from this year's taxes.  I did not re-calculate my 2016 taxes, but I did take advantage of the Recovery Exclusion form to figure out NOW whether my 2017 refund can be excluded from my 2018 tax return.  It was a simple form to use, and in my case, the answer was that all my refund can be excluded in 2018.  My AMT tax amount was about twice the amount of my refund, leading to my "nebulous guess" above.

+1 on TT should be doing this calculation for us.  Pisses me off that is doesn't

+1. TT should be doing it - Paying for a tax calculation software that doesn't do some tedious calculations is seriously frustrating.

If we redo the calculation, should we also be filing an amended 2016 return?

No, you're not actually making changes in your filed 2016 tax return.

It's is indeed really frustrating that TurboTax doesn't support this.

I work in finance with complicated spreadsheets and circuitous legal documents for a living.  I can NOT figure out how to refigure my return using the paper method.  I've spent half a day on this and the numbers are nowhere near logical.  User error no doubt.

So, if HarvardHolmes' assumptions above are correct, I will have an extra 2K of taxable income this year.

I'm spending 100 bucks on this software is it unreasonable to expect it to be able to do my taxes?

I found the form in 2016 filling and made the change  (question #2 of the Recovery form asks "is 2017 refund known" and I entered yes and the amount.  TurboTax recalculated the benefit.  NOW WHAT?  What number do I enter where in the 2017 filing?

The benefit amount is what you claim as taxable refund in 2017.

just to confirm do I make the change in my 2017 filing while in forms for Schedule A in the Computation for recovery Exclusion" form?  What other part of the filing does this change affect? Shouldn't line 5 of the AMT worksheet (6251) change?

You would change the amount entered as state tax refunded on line 10 of your 1040.

Where in turbo tax do I change the value for line 10?  Is it a form?