I don't know all the details of the Voit - Aqualung relationship, but if I recall it goes something like this. Voit was a significant supplier of rubber goods to Aqualung, and some arrangement was made where AL would share regulator patents as part of the financial trade agreements. What I don't know is if Voit had the regs manufactured, or if Aqualung manufactured them for Voit. I tend to think Aqualung built them since they already had the setup to do so. It would cost Voit a bundle to do that. Also, I don't see Aqualung letting someone else build the equipment to manufacture regs on their patents, thus potentially losing control. Hopefully someone on the forum can give us better details!
The older I get the better I was.