After talking to an IRS agent on 9 Feb 2021, it appears the response provided by TurboTax may be in error. According to the IRS agent, line 10b should accept an entry of up to $300 when using the standard deduction option, regardless of AGI. The agent said that IRS guidance/rule for line 10b has likely been updated between 2019 and 2020, and that TurboTax has not yet made the necessary changes to its software to handles this line 10b properly.
Currently, TurboTax requires line 10b be set =0, even though there has been a cash contribution to a qualified charity. TurboTax needs to be updated slo that if the standard deduction is chosen, line 10b is either defaulted to $300, or set to the amount of cash contribution entered elsewhere (Sch A?) if that is less than $300.
