Well....I have the Extreme set up MIDI Thru after the PA 4X at the same time and it starts and stops on a dime....

It has to be the PA 4X set up, but there is nothing I can see to set-up....

Now the Extreme has a box to tick saying RECEIVE EXTERNAL REAL-TIME COMMANDS option...does that make a difference?

Ugh...stuck for 5 hours