When armor smithing comes out you would lower level slabs to craft armor stakes that would be used in high level gear, say you want a level 60 metal chestplate you will need lower level slabs for the stakes on top of masterwork metal slabs in the required materials list or something along those lines not all stakes corresponding the level will be needed for the same tier armor for example a level 60 chestplate will take a level 50 armor stake which you will need expert metal slabs to make on top of masterwork slabs