When exporting from ETABS to excel what is exported is the Database units, not the present units. If you use the GetDatabaseUnits function you will see they are different than the present units.
I believe there is a SetDatabaseUnits which you can use in lieu of your SetPresentUnits function.
If...
It depends on what you're designing.
If you're designing the building's lateral system (the wall as you describe) then yes, you would combine windward and leeward coefficients. Depending on your layout you may also need to consider an end-moment acting on the top of this wall due to the uneven...