The margin is computed based on the average landed cost (ALC) and selling price of the product. The ALC is calculated based on the purchase price + any other costs associated with getting the stock to you (excluding taxes). Below is our formula for margin calculation for normal stocked products:
% (unit sale price - ALC) / unit sale price.
Product: Elderflower Sale price on SO-00064 = 9.96 ALC = 10.9232
Margin = % of (9.96 - 10.9232)/9.96 = -9.67%
Since all the products added to the SO have the landed costs greater than their selling price, this sales order is bound to have a negative margin. To see how the ALC of a product has changed throughout its existence in your system, navigate to the "costs" tab of that product record.
Alternatively, you can utilise cost analysis report to see the ALC changes of one or multiple products.