Standing, quoted, or isolated: classifying the discount you actually got

Undercharges get less attention than overcharges, which is a mistake. The pattern of prices below contract tells you more about the health of an agreement than the overcharges do — and it tells you what to ask for at renewal.

Standing discount

The supplier consistently bills below the contracted price for a product or family, across months and across jobs. That is not generosity; it is evidence that your contracted price is above market. The negotiation move is to reset the contract to the price they are already willing to charge, and to check whether the same gap exists on products where they are billing at contract.

Quoted discount

The lower price clusters on one job, one PO, or one date range. That is a project quote that never made it into your price list. The risk is that it silently expires and nobody notices the return to list. Capture quotes as dated price records so the audit knows the window and flags the day it ends.

Isolated discount

One line, one time, no pattern. Usually a keying error on the supplier's side. Left alone, it will be corrected by a rebill later, sometimes months later, and will look like an overcharge when it arrives. Classify it, expect the correction, and pair it when it comes.

How to classify mechanically

• Group below-contract lines by SKU and family, then by PO and by date window.
• Standing: present across three or more distinct POs and at least two months.
• Quoted: confined to one PO or one contiguous date range, with consistent magnitude.
• Isolated: single occurrence, magnitude inconsistent with neighbours.
• Surface the classification on the variance line so the buyer sees the story, not just the number.