The advance premium tax credit is paid to your insurer every month on the household income you told the Marketplace. Beginning with tax year 2026 any excess is repaid in full on Form 8962 - the old repayment caps are gone - so the IRS says to report income changes to the Marketplace promptly. Put in each month's household income as it closes; Sounding projects the year and shows how far it is from the figure on file.
When the projection drifts past the line you set, do one of two things: report the new figure to the Marketplace and record its reference here, or keep the figure on file and write down why. The line is yours to choose, not an IRS rule.