I'm not sure you're right. Do you know of cases to confirm this.
1. The language in the doc you linked just says you need to compare all QTP distributions for the year to the AQEE. But it doesn't say the AQEE has to be from the same year.
2. Further, see this discussion I've also see similar in many other places. in 2008 the official word was:
Section 529 is silent regarding whether distributions must be made from a section 529 account in the same
tax year as QHEEs were paid or incurred. Concerns have been raised that individuals could allow the account
to grow indefinitely on a tax-deferred basis before requesting reimbursement or use distributions in earlier years to pay QHEEs in later years. Accordingly, the IRS and the Treasury Department propose to adopt a rule that, in order for earnings to be excluded from income, any distribution from a section 529 account during a calendar year must be used to pay QHEEs during the same calendar year or by March 31 of the following year. The IRS and the Treasury Department welcome comments on rules necessary to ensure that distributions from section 529 accounts are appropriately matched to the payment of QHEEs.
But I can't find record they actually went through with this change. So they admitted it's unclear and never clarified. Or do you have evidence they clarified this?
Here's another even better thread on the topic
https://www.reddit.com/r/tax/comments/16ytao5/529_retroactive_withdrawals/
