hrms...
I always thought the way those solenoids worked was to restrict a pressurised source going to the waste gate thus stopping it from opening, once the desired pressure is reached, the EBC controller then sends a signal down to the solenoid to pulse so just the right amount of pressure to open the wastegate.
I didn't think EBC bled air, it depends how you connected the ports, happy to stand corrected
(I use a Blitz dual solenoid)