Selling costs typically include the amount of money was invested into its development, marketing, and distribution. This metric informs your team as to how much actual revenue is gain, with the additional information of how much of the final sales value goes back in to cover the cost the company took on to make the sale.
Cost of selling/Total value of sales
Example of KPI target
8% of value
CFO, Sales Manager
Selling costs to sales value
Marketing expense to sales ratio