So, we have had issues with our ESAs pausing for anywhere from 30 seconds to 5 minutes and they thought this was the issue, so here is how it was explained by TAC.
The listener is for just that listener, and global is for the device, so if you don't want a bottleneck, global should be equal or greater than the total of all listeners. IE, if you have 5 listeners each set to 100, then global should be at least set to 500. if global was also set to 100, then you could see each of the 5 cap out at 20, or 1 listener could use all 100 and the others would get 0 since the global cap was hit.
Hope that makes sense.