What are PID changes Scott?
I will let one of the technical guys answer that.
The PID change I know about.... I'll put in layman's terms. Each video stream is assigned a unique PID on the transponder, commonly referred to as the mux. The PID is basically the video streams address. The channel table loads into you receiver based on the satellites you have in your setup. When you want to tune to USA-HD, the table tells it to turn to a certain satellite and transponder, then decodes the correct address of the video and audio out of the mux. They could change PIDs around all day and it wouldn't really make a difference to the end user like say the EPIX3 channel being added makes a difference to you.