You may want to consider a dedicate microcontroller to do this for you. It could monitor the 5vdc line to know when the PC is turned on, and move your servos for you, you could still use the shut down script to close it down. I know it would add a lot of complexity to what should be a simple procedure, but it would work.
Oh wait!
If you can live with it for a little while we will be offering an upgrade to the SSC-32’s processor and firmware to allow some interesting features. The one you will be excited about is it will allow startup sequences to be added that automatically run when the servo controller is first powered up. So as soon as the SSC-32 is turned on it will initialize the servos at the closed position, then slowly open them to the full open position. They can stay that way until the shut down script closes the doors. then the power is shut down turning the SSC-32 off.
It’s going to be a little while longer for this. We are working on it! 