I think it isn't that easy. Just raising or lowering the level
of a performance means a lot of going back and comparing with other performances, rig by rig. And you can find some unexpected behaviors.
I'm a newbie who is still getting used to the Kemper, so I haven't suffered that, but that day could come soon.
Maybe it would be a good idea, when creating a performance, to "sacrifice" one of the performance's slots and place there a rig (always the same one, of course) you know well and use it to level the other rigs in that Performance. When it's done, you can put another rig in the sacrified slot.
I'm sure some people do that long ago, so excuse me (as I said, I'm new, here.)