An invoice can look perfectly normal and still leave out the discount you agreed.
A supplier agreement often sets your price as a discount off the list price, the supplier's price before discounts. If the agreement gives you 30% off an item listed at NOK 1,000, you should pay NOK 700.
When the supplier bills the list price, or applies a smaller discount, you only see the error if you know the agreed discount and work out the price yourself.
Two Watchdog examples
Billed at the full list price
The case
A Norwegian municipality buys toys and craft materials under a framework agreement, which sets prices and terms for everything it orders from the supplier over a fixed period.
What the agreement said
Some products have fixed prices. Everything else in the supplier's range comes with 58% off the list price.
What was invoiced
In May 2026, the supplier billed two building sets at their full list price. One was listed at NOK 10,166 and should have cost NOK 4,270. Three later invoices, through July, gave a discount on other products, but less than 58%. In all, the error appeared on four invoices from one supplier in about two months.
- Invoices
- 4
- Overcharged by
- 76.4%
- Total overcharged
- NOK 10,370
A smaller discount than agreed
The case
A mid-sized Norwegian company buys industrial supplies, such as bearings, wheels and pneumatic parts (parts driven by compressed air).
What the agreement said
A separate discount off the list price for each product group, for example 72% on bearings and 45% on pneumatic fittings.
What was invoiced
Between September 2025 and August 2026, 14 invoices gave a smaller discount than the agreement, 4 to 25 percentage points short. The list prices were right. A few points matter more than they seem: with 72% off you pay 28% of the list price, with 68% off you pay 32%, so each bearing cost 14% more than agreed.
- Invoices
- 14
- Overcharged by
- 7.2%
- Total overcharged
- NOK 14,497
Our recommendation
A discount you can't see on the invoice is hard to check. Ask the supplier to show the list price and your discount on every invoice line, and make sure the agreement says which list price the discount starts from, such as a dated price list.
Check the discounts again whenever something changes on the supplier's side, such as a new price list or a new ordering system. If a discount has been missing, ask for a credit note covering every invoice since it went missing, not only a fix for the next ones.