Cost per variant in the variants table

The "Variants" table on the Selling tab has a "Cost" column - set what each size or colour costs you, an XXL more than an S for example. The "Set for all" row fills it for every combination at once, and an empty cell inherits the product's cost. Order profit and margin are worked out from it. In "By batch" mode the cell shows the average cost of the variant's batches.