True, you can't amortize twice, but you can amortize the cost of the .45 dies.I do it that way because it would skew the numbers if you bought the press to reload 9mm, and amortized in the cost of the equipment on that price, then added .45 later. Well, you already included the cost of equipment in the 9mm price, so you can't add it to the .45.
Now I've got an idea of something to do in Excel...
*scurries off*
I try to avoid spreadsheets whenever I can. Depressing damn things, they are!