what is correct tax amount
I am filing for my mother-in-law on TurboTax. She is filing single and her taxable income is $17,603. Base on IRS 1040 and 1040-SR instructions 2020 Tax Table, should pay tax $1,918 but TurboTax calculated her tax $1,876. Should I be concern that later IRS found her filing short $42 and imposed penalty?
Thank you,
Zulfi B.