If you have a look at the circuit diagram you see that I CANNOT leave it like it is. After I cut the connection of the two middlepoints and leave the connection of the two halfcoils I have one single coil on each side no matter if the two were symmetric or not. Actually they were, each halfcoil had 20Ohms and now I get 40Ohms for each full coil.
It is true that I now need (or can) drive the motor with double voltage but this doesn´t matter, important is that it works 