Customer sells a particular item individually or in cartons of 12 each. If not sold in a carton, price is $40.08. Carton pricing is $384.72 ($32.06/each). So, if customer buys 24 items, total price is $769.44 ($32.06/each for all) but if they buy 25, total price is $1,002.00 ($40.08/each for all). What would be best way to set this up? Thanks!