IN Settings - Rounding tab

Navigator > Setup > Invoicing System > Settings > Rounding tab

Invoice totals may need to be rounded when supplying goods or services for cash, for example, to the nearest five cents. Each invoice is rounded depending on the final digit of the invoice total. Each digit from 1 to 9 can be rounded to another digit from 0 to 10. Note that rounding to 10 rounds up to the next 10 cents. When rounding to the nearest 5 cents, round off (positive or negative) will be analysed to the Rounding charge to ensure Sales Analysis always balances.

By default, Banking Media Rounding is Selected for new companies.

See also IN Settings - General tab.