I've had a lot of problems with the add-on, specifically corner conditions aren't always correct and not fixable when some corners are inside and others outside as when you have an L shaped room.
Use the custom profile tool instead to add trims to your walls as suggested.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"