There are some special rules that sometimes come into play when calculating line 5 of Form 8962 that might account for what you’re seeing.
Please see Line 5 and Worksheet 2 – Household Income as a Percentage of the Federal Poverty Line in the IRS’ Instructions for Form 8962 for more information.
If this isn’t helpful for your scenario, please provide additional information. Your entries on lines 1 - 4 would be helpful, as would the entries that the program is displaying for Part I of the form.
