It doesn't matter. As you have identified, room and board are not qualified expenses for the education credit or for tax free scholarship. It also doesn't matter if you actually used the 529 funds to pay for R&B. All that matters is that the 529 distribution occurred in same calendar year that R&B was paid and that the total amount of R&B paid was greater than or equal to the amount of the distribution from the 529 plan (box 1 of the 1099-Q).
You are not required to report the 529 distribution on your tax return (or the student's).
When the box 1 amount on form 1099-Q is fully covered by expenses, TurboTax will enter nothing about the 1099-Q on the actual tax forms. But, it will prepare a 1099-Q worksheet for your records.
On form 1099-Q, instructions to the recipient reads: "Nontaxable distributions from CESAs and QTPs are not required to be reported on your income tax return. You must determine the taxability of any distribution."
