Since the amount is never the same each semester and not known ahead of time, I paid for my kid's college books out of pocket. I then reimbursed myself with an electronic draft from his 529 account to my personal checking account. How do I account for the reimbursement within the software?
When using TurboTax and a 529 account is in play, it is *IMPERATIVE* that you work through the Education section the way it is designed and intended to be used. If you do not, then changes are very high (like 99.9%) that you will not be asked for those expenses that can be claimed on a 529 account.
So work through the education section again from the beginning of that section, and work it the way it is designed and intended to be used. Then you will be asked for all the education expenses you are qualified to claim.
Also note that if you made the out-of-pocket payment in 2017, but did not reimburse yourself from the 529 until 2018, then you have NOTHING to report concerning the 529 transaction on your 2017 return. You can not claim it until you file your 2018 return, and the 1099-Q you will receive in 2019 will show your 2018 reimbursement.