Now isn't the 3va/sqft deal for calculation, not connection?
The circuit needs to be sized for what it is connected to....
Balance is not required, but strongly implied that some idea of balance on the connection is what they're looking for right?
Anyway, rknikko, I have had problems with AFCI's on certain types of loads. Dimmed LV lighting, flouresant lighting, and a flat screen monitor. If this type items have problems on a 2-wire circuit, why bother trying to chance it with a 3-wire?