I suspect dual ejectors solve a number of possible issues. You can bring the plungers closer to the center of the case head so the your increasing the effective travel of the plunger wile not ejecting it at a high or low angle. Probably keeps the thrust more square with the exractor too.
Right now I'm battling what I thought was a good purchase lately lol. savage that someone has installed a 300 blackout barrel... ejects maybe 1 out of 5 cases lol.