For e-filing, the IRS requires all amounts that are transmitted individually to be rounded (50 cents or more rounding up to the next dollar, and 49 cents or less rounding down). Since each line of the Schedule B (Form 1040) Interest and Ordinary Dividends is transmitted for e-filing, each amount from Form 1099-DIV Dividends and Distributions, Box 1a gets rounded individually since it is listed on Schedule B individually.
IRS Instructions for Form 1040 and 1040-SR, on page 22, states that if you are adding up multiple amounts to enter on one line of a schedule or a form, you should add the amounts and then round the total. TaxAct® adds the amounts from Form 1099-DIV, Box 1b and then rounds the total.
Left as-is, it would cause no problems with the IRS. Our program was tested by the IRS and has been approved. If you would like to see them be the same amount, you would need to modify one of your individual entries by a slight amount.
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.