Calculate the same cost basis first
For each confirmed item match, compare the old and proposed net cost per sellable unit. If the supplier changed pack size or unit of measure, convert both sides before calculating the difference. If it changed a discount multiplier, include that in net cost. The pack-size guide and calculator show the arithmetic. Do not rank a box price against an each price.
Then use a forecast that your buyer recognizes, such as expected units purchased in the next month. A simple screening figure is (new unit cost − old unit cost) × expected units. It estimates additional purchase cost if the volume and other terms stay the same. It is not a sales forecast, a margin calculation, or an approved price change.
Separate increases, decreases, and unknowns
In the fictional RowTune sample, a brass valve rises from $10 to $11 per each. At 80 expected units, that is an estimated $80 in extra purchase cost. A box of pipe clips changes from $100 for 10 to $225 for 25, so unit cost falls from $10 to $9. At 800 expected clips, that is an estimated $800 decrease, not an increase to rank with the valve. The sample's elbow has an uncertain match, so its apparent price change stays on the hold list until someone confirms the item.
| Fictional item | Old → new / each | Expected units | Estimated cost change |
|---|---|---|---|
| Brass valve | $10 → $11 | 80 | +$80 |
| Pipe clips | $10 → $9 | 800 | −$800 |
| Uncertain elbow match | $2 → $2.20 proposed | Unknown | Hold, do not estimate |
Within the confirmed increase group, sort by estimated extra cost, then use the percentage change to understand how steep each increase is. The exposure number is a queueing aid. Check whether purchase volume is seasonal, whether an open order uses old terms, and whether a customer commitment makes one item urgent. If volume is missing, mark the estimate unavailable instead of entering zero. A zero would make an unknown item look harmless.
Keep exceptions ahead of the numeric queue
An ambiguous SKU, a missing pack quantity, a currency change, or a date conflict cannot be made safe by a small calculated impact. Put these on a separate hold list with an owner and the question that needs answering. The increase-letter review helps check the supplier's stated scope and exclusions against the actual item file.
After the buyer resolves those exceptions, record each decision and only then prepare the approved output. RowTune supports item matching, change review, and export of reviewed lines. The projected-volume ranking in this article is a manual planning method, not a claim that RowTune forecasts demand or automatically chooses which costs to approve. Start with the full comparison guide if you still need to establish the old and new cost baseline.