Project, task, and details are stored in table 1003: ProjectPlanning Line. Microsoft Dynamics 365 Business Central recognizes three types of that line: Budget, Billable, and Both Budget and Billable.
Because Industrial Equipment Manufacturing (JMS) clearly separates budget, planning, and billing, an additional type has been added: Planning. The Both Budget and Billable type is hidden. Industrial Equipment Manufacturing previously had separate tables for budget and billing lines; these no longer exist.
The Copy Budget to Planning action copies a planning line of the type Budget to a new planning line of the type Planning by changing the type.
Table 1003 can grow quite large. To accommodate this, the following archiving rules apply:
When a project quote is converted to an order, only the active budget is copied. All other budget versions are archived.
When a project is completed, all planning line types are archived.

In Industrial Equipment Manufacturing, the planning line has three types: Budget, Billable, and Planning. The line type is not editable but is set per page:
In the Budget Lines page, you can only create lines of the type Budget.
In the Planning Lines page, you can only create lines of the type Planning.
Planning lines are also created by the Copy to Planning Lines action.
In the Billable Lines page, you can only create lines of the type Billable.
Billable lines are also created by the Initialize action that breaks down a contract amount.
Billable lines are also created when usage is posted in a project with invoicing method Time and Material.