Tax exempt dividends in Box 10 are $324.19. When I total percentages by state, the total is $314.70. What should I do?

You don't have to do anything. Totalling by percentages won't get you the exact amount. The percentages are truncated, meaning there are additional places that don't show on the form

You don't have to do anything. Totalling by percentages won't get you the exact amount shown in Box 10. The percentages displayed on the form are truncated, meaning there are additional places that aren't displayed