The extra zones allow more Second Skin options, without having to composite the clothing texture over the skin texture. In DAZ|Studio it's simple to select an appropriate surface, such as SkinFeet, hit the Copy button, select the new surfaces, hit Paste: I think you can do much the same in Poser 5 and 6 using the Material Room (except you can't multi-paste) but I haven't tried it yet. For Poser 4/ProPack it is a nuisance - time to load Mat pose Edit I suppose.