Different rafters over different rooms & Ceiling Elevation Problem

[EconBlueprints]

Is there a way to have different rafters in different rooms?  
I have one room where I need the rafters to be 2x6, and another to be 2x10.

Also, in the attached plan, the first floor plan view ceiling height for the garage wants to be 96", Top Of Slab (Floor) to Bottom of drywall.
Ceiling height is set @ 96-5/8"
Drywall is set @ 5/8"

When I open the Rooms Specification Dialog box, under "Relative Heights" The Ceiling is set at 96 5/8", but in the diagram section  to the right it shows that same dimension as 95 1/8".
For the Finished Ceiling, the Dialog Box is set at 96", but in the diagram section it shows as 94 1/2".
How do I set it up so the finished ceiling is actually 96" and it will also show up as 96" in the Elevation View (E1) and the story pole to the correct dimension?
Plan is attached. 

New_Floor_Plan.plan

[Renerabbitt]

16 minutes ago, EconBlueprints said:

Is there a way to have different rafters in different rooms?  

a simple way of doing this is splitting a roof plane and setting different members for each.