Everything in Prod. codes goes to cost, whether the amount is positive or negative. A negative item reduces the cost and increases the contribution margin. It can stay as a minus if it is meant as a real cost reduction.
How to check the item
Find the negative item in Prod. codes.
Clarify what the item is: a discount, a reduced purchase or a purchasing gain you are to recover.
If the contract sum is already net after the discount, the discount must not be deducted a second time. Remove or correct the item.
If the item is a purchasing gain you need to recover, it can stay as a negative cost.
Check the effect on the contribution margin on Home.
Good to know
The wrong sign gives a double effect on the contribution margin.
Estimates from other systems may have 800- or 900-codes with a special meaning. In AIMZ these are ordinary cost lines.
If a purchasing gain is entered as a negative cost, successful purchases are shown as a positive remaining budget.