It has been a while since I did the D9P, but instead of twisting your blocks, I think it works just as well if you just switch two of the opposite corners. Try putting the four pieces back in place the way they were right after cutting into 4ths then switch the positions of the lower left and upper right blocks. The individual re-sewn D9P blocks will look different than if you use the twist method, but once you put them all together, the effect is the same.
Either I am correct or it is jut too late and I need to go to bed....LOL!!