Hi cat,
I don’t see any mention about “mini layers” or zoning customizations for the on the Organicpedic Duo page so as you mentioned this may be something they’ve added to zone the mattresses at a local level along the lines of post #11 here.
While zoning can certainly be a useful options if the zoning scheme “fits” the person … if you do decide to go in this direction I’d want to make sure you have the appropriate or “official” layers for the Duo including the solid sculpted layer on top and not a more “random” selection of layers or zones that may not be the best combination for you.
Phoenix