Yes, you are correct.
The MESH type is actually including TONS more geometry into your scene, and duplicating brushes just makes things worse.
I'm glad you found the correct way of solving this issue, so I am going to make this post STICKY so others may be able to learn from it
Great job!
Izzy
Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com