For Lean Manufacturing in Odoo 19 without Work Centers, the simplest approach to capture direct labor cost is to add a Service-type product (e.g. "Direct Labor") as a component in your Bill of Materials (BoM) with a fixed cost. This way, labor gets included in the manufactured product's standard cost without requiring Work Center time tracking.

Steps:

1. Create a product "Direct Labor" with type = Service and set its cost price (e.g. per unit or per assembly).
2. 2. Add this product as a component in your BoM with quantity = 1.
3. 3. Set the correct accounting account on the product (e.g. a dedicated "Direct Labour" expense account) for proper accounting separation.

For sub-assemblies with separate stock valuation, create a separate finished product for each sub-assembly with its own BoM, including its own Direct Labor component. This gives you separate stock valuation accounts per sub-assembly. Odoo's Average Cost (AVCO) or Standard Price costing method will correctly roll up the full cost including labor.