When the BAC is plugged in and the initial set coupler is NOT jumped, the idle set screw changes the idle RPM. Is this normal or is my BAC bad?

 

I would say its normal.

 

Normal. The idle screw is allowing more air past the throttle body, raising the idle.

But you won't be able to lower it past what the BAC will allow and the ECU might try to compensate by altering the BAC.

The initial set coupler basically disables the BAC and locks the timing.