Hi Cro Aloha,
Most of the algorithms in PF have two shifters. In true stereo mode the A shifter is on the left channel, and the B shifter is on the right. That is why they come out panned like that, because the box is true stereo. If you want to do 3 part harmonies with both channels you should try Quadravox. Set A and C to the first interval, then B and D to the second interval. You will then have a true stereo 3 part harmony.
Dan
