Your tax preparer is correct. The tuition credit is applied to the year the expenses were paid (as long as the 3 month rule is met).
However, there is frequently a mismatch of years for box 1 and box 5. That portion of the scholarship would not be taxable. It may best be explained by example. Suppose you were billed for $10,000 in December 2020 for the Spring 2021 term. Your parents only paid $7000 because they knew scholarship would pay for $3000. The school didn't apply the $3000, to your account, until January. So, that $3000 was included on the 2021 1098-T, instead of the 2020 1098-T. That $3000 isn't taxable
The 1098-T is only an informational document. The numbers on it are not required to be entered onto your tax return. However receipt of a 1098-T frequently means you are either eligible for a tuition credit or possibly your student has taxable scholarship income.
You claim the tuition credit, or report scholarship income, based on your own financial records, not the 1098-T. In the 1098-T screen, click on the link "What if this is not what I paid the school" underneath box 1. You will then be able to enter the actual amounts paid. You will also reach a screen that allows you to adjust the scholarship amount for "amounts not awarded for 2021 expenses".
