I know that there is an option to show the gross margin obtained from a sale in the SO and Invoice. I have seen some tutorials that shows how to calculate commissions over the gross margin generated from a sale. I have Odoo Enterprise 10 and when I create a type of commission, there are just 2 options gross base (gross amount of the sale) or net base (amount with tax included), but there are no gross margin option. Anyone can tell how to calculate commission over gross margin?