FIFO Inventory Layering in a Standard Cost MFG Environment

Riddle me this... How can we setup a standard cost environment that can handle FIFO layers for inventory.  A large manufacturer create 100 tons of inventory (still on hand) in 2012, come 2013 we will change the standard cost of new production based on projected sales, budgets and overhead rates.  We cannot take a huge gain or loss on day one without selling or producing anything financially, so we create a lot for 2012 Inventory, and a lot for 2013 which we produce into and change the cost level to 3.  We also change the commitment method to smallest lot number on the selling