Dr. Rip:

Is Stig's explanation enough, or do you also want to know how to set things up?

True, you only have one EFX processor + chorus + reverb for your 16 performance parts, but how you set it up makes all the difference. You can get instruments to sound the same in patch and perf mode (actually, in two different ways), but it may not be immediately apparent:

(1) copying the EFX settings from patch mode into perf mode
(2) setting up the perf EFX source in a certain way

Let us know if you (or anyone) want to go further with this.