Not computing cost_price of service products?

I have a doubt, that the cost_price of the service products it’s not being computed, I have only seen functions that are computing the cost_price from the moves. But service products only have purchase_lines linked. I want to show the average cost_price of this service. That makes sense to do it?. There is some way that is computing the cost_price of the services from their purchases. In the case that there isn’t a way, what is the criteria to don’t compute the cost_price?
Thanks beforehand.

There is no method to know that. You only need the cost price for accounting, as legally you need to be able to know the value of your stock.
Also the cost of service offered by a company it not only the price of purchased lines.
There are multiple factors that can be affecting the cost, ask a cost controller about different possible costs, but only to mention a few: marketing, labour hours (+extra hours), energy consumed, tools and machinary…

Tryton supports only fixed cost price for service for now.
Maybe when Add module to allow services to be invoiced when they are done (#9999) · Issues · Tryton / Tryton · GitLab (with the purchase equivalent), we will be able to add more methods.

A post was split to a new topic: How is recompute cost price done