For a management report simplified display just showing whole numbers is appropriate as the reader is interested in concepts not actual numbers.
In form for submission to your tax authority actual numbers and legally permitted rounding options matter.
For example in an annual tax return to the ATO
- income subgroups are rounded down (floor)
- total income must be the sum of the rounded values
- expense subgroups can be rounded up (ceiling)
- total expenses must be the sum of the rounded values.
- net taxable income must be income total minus the expenses total. Which typically differs from the same calculation done to 1 cent precision by multiple dollars.
- in a trust the after tax profit is the distributed, the amount available for distribution varying if a different amount if tax is actually paid.
In summary for submissions to a tax authority rounding requires
- specification of rounding method of sub values (floor, ceiling, or rounded)
- addition / subtraction of intermediate values