Così Prices

Look at these two menu items and see if there is a significant difference:

1. Tuna Cheddar Sandwich: Homemade tuna salad, cheddar, shredded romaine & Così vinaigrette.

2. Tuna Melt: Tomato, melted sharp cheddar and Così vinaigrette.

The sandwich has lettuce while the melt has tomatoes. Otherwise, they both have tuna, cheddar cheese and the Così vinaigrette. So why is it that the melt costs $6.39 while the price of the sandwich is $5.99? Does it really cost 40 cents just to put the tuna melt in a toaster?