A worked example: 9.33% of 512.75
Suppose a commission rate of 9.33% applies to a sale of 512.75. The percentage formula gives an exact result of 47.8396 — (9.33 ÷ 100) × 512.75. That figure is mathematically correct, but it's an awkward number to write on an invoice or read aloud: a real payout isn't usually quoted to four decimal places.
Chaining in the rounding step: 47.8396 becomes 47.84 or 48
Feeding that same 47.8396 result into a rounding step, set to 2 decimal places using the "nearest" direction, produces 47.84 — a clean two-decimal amount suitable for currency. Rounding the identical 47.8396 to 0 decimal places instead gives 48, a whole-number estimate. Both are legitimate roundings of the same exact percentage result; which one is appropriate depends on whether the context calls for currency-level precision or a rounded estimate.
Why these stay two separate calculations
The percentage formula and the rounding formula solve different problems and don't get merged into one step: the percentage formula answers "what is X% of Y," while rounding answers "how much precision should this specific answer keep." Keeping them separate means the exact result (47.8396) is preserved as an intermediate value — useful if it needs to feed into a further calculation — while the rounded version (47.84 or 48) is reserved for whatever gets displayed or recorded as the final figure.
When rounding the intermediate result would be a mistake
Rounding too early — say, treating 47.84 as the number to work with in a further calculation rather than the exact 47.8396 — can introduce small errors that compound over multiple steps, such as when a percentage result feeds into a running total across many transactions. The safer pattern is to keep the exact percentage result for any further math and apply rounding only at the very last step, right before the number is displayed or recorded.