I always considered my plans built planes scratch but do to politics and egos I now say scratch built from plans, keeps the peace.
Every set of plans I have ever gotten needed to have sections redrawn anyway or redisigned for one reason or another. Old designs and new ideas and gear plus I like to do things my way.
Call it what you want. Making model planes was always A hobby when I was A kid, now days the building is the hobby and to fly them is A sport??????? Go figure!