I was actually really wondering about this. The "PE" map doesn't make any sense to me, why not just add those values to the base map? I was thinking about zeroing it out and adding to the base map instead.
Regarding the trims, I don't have a wideband yet so my normal method is to reset the ECU trims then drive around for 30-40 min and go off the LTFTs. Won't disabling closed loop eliminate this as a tuning option?
EDIT:
I guess it makes sense in the context of emissions compliance. There's a PE and PT enrichment delay, so if you were to simply add the fuel in the base table you would get better drivability and more power but you'd have worse emissions. Still, I'm half inclined to zero out the PE and PT enrichment tables and add that fuel to the base table. Then you could more easily predict what will happen and smooth out the graph in a way that makes sense.
IDK, that just seems easier to me and would allow more consistency.