If you upload prices in the form of selling prices with some kind of commission (for example 10%)

1. Enter a new price list
2. There is 1 price list row predefined.
3. Locate the Net line of that price list row and enter net prices in all periods.
4. Locate the price list row tool box in the last column of Net line.
5. Click the C button in the price list row tool box in the last column of Net line for some amount.
6. Click OK to save changes.