I have a default margin for this price list but it isn't working for all my line items.

I have a default margin for this price list but it isn't working for all my line items.

Check if there is value in the "Mrgn" column for that SKU Item in the Administration/SKU Items table in the bottom left. Margin set for individual SKUs override the price list margin. In that case, you could override the revenue of that SKU item if you want it to match the price list margin.

In this example, the Default Margin for the "Retail" Price List is 20% but the SKU Item, "Bianco Nube 3CM" has a 30% margin.