I spent $5,768 on my daughter's grade school using my 529. I got a 1099-Q showing this amount and my daughter as recipient. Why does TT say this doesn't affect my return?

There is no federal deduction for the use of 529 funds but any withdrawals including earnings from the account are not taxed if used for qualified education expenses. 

No.  K-12 education expenses are not deductible.  The advantage to using 529 funds to pay those qualified K-12 education expenses, up to 10K per year, is the earnings from your 529 that you used are not taxable.  As long as the distributions were used for qualified education expenses (including K-12) you do not need to enter the 1099Q information on a tax return.  Be sure to keep records of how the amount was spent in case it ever comes up.

Q. Since I used after-tax dollars to put in the 529 I thought I'd get a deduction for these expenses?

A. No. It doesn't work that way. 

There is no federal deduction when you take a distribution from ( or for making a contribution to)  a 529 plan. The tax break comes, when you take the money out to pay for education.  All earnings (interest, dividends and capital gains) over the years is tax free if the distribution is used to pay for education. . In the case of K-12 schooling, there is a $10K/year limit and tuition is the only qualified expense. 

Some states allow a deduction, for contributions,  on the state return. If your state is one, it would have come up in the state interview. The deduction is taken back in the year the contribution was made (not now, when you take a distribution).

For a state list of eligible plans, see: https://www.savingforcollege.com/529-plan-details

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