When creating cost plan details you have to option to Populate from Team or Task Assignments create a manual plan and enter lines manually or you can do a combination of both.
How can you tell which lines were auto populated vs which were manually entered?
Release : 15.9.1
Component : CA PPM SAAS FINANCIAL MANAGEMENT
To find the answer you would need to query the fin_cost_plan_details table and also know the internal plan_id.
You can find the internal plan_id in the URL and it will be similar to '...plan_id=5005001'
You can then run query
SELECT * FROM fin_cost_plan_details WHERE plan_id = <Enter plan_id>
SOURCE: RESOURCEPLAN = Populated automatically
SOURCE: COSTPLAN = Line entered manually in the cost plan.