I have a client and her husband, whose entire income is derived from interest, dividends, and capital gains (not taxed), plus a retirement income which is taxed, and social security income.  Because of huge investment income, their  tax liability shot up to over $10,000 for 2023.  Proseries computed an underpayment penalty of $188.00, which was included in her taxes due.  I received a notice from her that a check was issued to her for the $188.00.  Apparently, IRS determined she was not being penalized for the tax liability.  Does IRS charge underpayment penalties on income solely derived from investment income?  Also, how can I stop Proseries from computing penalties and interest?

I would rather IRS compute it sinc