State tax filing

The Unified Credit for the Elderly is up to $140 for married taxpayers when both spouses are 65 or older. However the actual amount the couple qualifies for depends on income level. They would only qualify for the full $140 if their federal adjusted gross income is under $1,000.

If their income is at least $1,000 but less than $3,000, they would qualify for a $90 credit.

There is no $90 credit for single taxpayers or married taxpayers with only one spouse being 65 or older, so it seems the couple's income is between $1,000 and $3,000 and TurboTax is correctly calculating the credit.