Start with the evidence
Keep the unrounded calculation and the displayed precision visible. Use the rounding method agreed for the actual task rather than changing it solely to force a match.
Work through the example
EUR12.34 at a fictional USD1.10 per EUR gives USD13.574 before rounding. Displaying two decimal places gives USD13.57 in this example; the working note should explain where that rounded figure came from.
Make the next step clear
Compare the method used across the records under review. If line-level and total-level rounding differ, describe the difference for the reviewer instead of disguising it as a fee.
Keep the source context
All exchange rates in these worked examples are fictional arithmetic inputs, not current market rates. A business must use the source, date and method appropriate to its own review and approved accounting process. Keep original currency amounts available throughout.