Keep a mid-period rate change tied to its dates
Use sale-date agreements for a mid-period rate change, check the boundary and preserve the rate evidence in the final record.
Changing one percentage halfway through a week creates two calculation segments, even if payroll still uses one week. The evidence needs to identify the effective date, the sale date used for eligibility, and the rate on each side. A new rate entered today should not silently rewrite the explanation of an earlier close.
The useful part
Separate the source rows by the confirmed effective date, calculate each segment under its own rate, and retain both segments in the final handover.
Define what the effective date means
Write down the old rate, new rate, effective date and the date field that assigns sales to each rate. Invoice date, appointment date and payment date can place the same transaction on different sides of a boundary. Use the field agreed for this calculation rather than whichever report is easiest to export.
Also identify whether the change affects service, retail or both. Keep the evidence of the confirmed arrangement with the rate register. This guide demonstrates applying supplied rates; it does not determine whether a proposed employment change is valid or appropriate.
Calculate the two segments independently
The fictional service rate changes from 40% to 45% on 24 September 2026, using the source invoice date. All figures below are already the supplied commission basis, so no additional tax removal is needed. The reporting week remains 21–27 September.
| Invoice dates | Service basis | Applicable rate | Commission |
|---|---|---|---|
| 21–23 Sep | $600.00 | 40% | $240.00 |
| 24–27 Sep | $800.00 | 45% | $360.00 |
| Whole week | $1,400.00 | Two documented rates | $600.00 |
| Incorrect: new rate on all sales | $1,400.00 | 45% | $630.00 |
Check the exact transition rows
Inspect the last invoice before the change and the first invoice on or after it. Confirm the date format and the report timezone if timestamps were converted into dates. The new segment begins on 24 September in this example; 23 September belongs only to the old segment.
Search for refunds crossing the boundary. In a dated workspace, Trimsum selects the agreement covering the refund row’s own date; it does not trace that row to the original sale or automatically reuse the original rate. If the confirmed adjustment calls for a different rate, document the original calculation and use a separately reviewed adjustment process when the ordinary dated rule cannot represent it. Do not backdate the refund to force a result.
Set the date ranges in the workspace
A dated Trimsum workspace links imported rows to stable staff identities and selects one service or retail agreement by each row’s sale date. Upgrading an existing flat-rate workspace is explicit: review the migration preview, download a full backup, then confirm the upgrade. Existing staff rates become agreements from 1 January 2000 with no end date; earlier finalised runs stay fixed. Workspaces that have not been upgraded still use their existing single current service and retail rate per person.
For this example in dated mode, set the first agreement to 40% and end it on 23 September, then add a 45% agreement beginning 24 September. End dates are inclusive. Overlapping intervals are rejected, and a date with no covering agreement keeps affected sales on hold. Check the calculated rate and agreement date range on the last old-rate row and first new-rate row before finalising the full week. Changing dates or rates reopens affected draft approvals for review; it does not rewrite a closed run.
If you keep the legacy flat-rate model, review and finalise the first date segment using its confirmed rate, then change the current rate and close the next date segment separately. Check for unresolved rows before each close. Preserve both run exports and their rate-change evidence.
Keep one real staff identity
A rate change does not require a second person. Link source names and aliases to the same staff identity, then use dated agreements or clearly separated legacy runs.
Combine segments without losing their evidence
For a dated full-week run, show both agreement date ranges and the line-level rates in the detail export. For two legacy runs, create a cover sheet with both date ranges, run labels and their combined commission, then attach both detail exports. In either workflow, the example’s $240.00 plus $360.00 equals $600.00; keep the rate-change record with the handover.
Keep the separate line calculations rather than replacing them with a blended percentage. A blended figure can reproduce one total while hiding the effective date and failing on the next dataset. The recipient needs to trace each line to its applicable rate, not infer a new agreement from an average.
Test the change before repeating the process
Use the rate comparison tool to show the financial effect on the same sample basis. In this case, applying 45% to the old $600.00 segment would add $30.00. That isolates the source of the incorrect $630.00 whole-week result.
Before the next close, confirm which agreement covers the new sale dates and whether any earlier-period adjustments remain. Preserve the effective-date record as evidence and update the operating checklist. If the arrangement needs tiers, per-service rates or several simultaneous effective rules, keep a separate reviewed calculation until the app supports that model.
Put it to work.
Follow the source rows, calculation and review decisions in a sample workspace.
Explore the worked example