I am unaware of any IRS rule requiring rounding to near dollar. It appears to be optional.
Here is some language from Form 1040 2020 Instructions :
Rounding Off to Whole Dollars
You can round off cents to whole dollars on your return and schedules. If you do round to whole dollars, you must round all amounts. To round, drop amounts under 50 cents and increase amounts from 50 to 99 cents to the next dollar. For example, $1.39 becomes $1 and $2.50 becomes $3.
If you have to add two or more amounts to figure the amount to enter on a line, include cents when adding the amounts and round off only the total.
If you are entering amounts that include cents, make sure to include the decimal point. There is no cents column on the form.
It appears TurboTax software forces the whole dollar filing option. In this case it cost you $5.00.
