After getting two separate answers from Citrix, I finally have the numbers golden on the timeout values between the Desktop Delivery Controller and the Virtual Desktop Agent. It is 3 minutes on powerup and 5 minutes on powerdown. I think these should be tweaked in some large Virtual Center environments, due to task queuing. I think they can be in the machine registry hosting the VDA, but not sure if the DDC has to be modified. Something to look into…. If anyone knows, please comment.