What your saying is that frozen ice doubles. I'm not sure what kind of water your using. I would think that at the very most you would lose 1 cup so double strength coffee makes perfect sense.
Recipe America Iced Coffee
To make Iced coffee, select a Dark coffee roast. Use twice as much coffee as is required to brew a regular cup of coffee. If on the coffee can it says one tablespoon per cup, use two tablespoons per cup. If you want sweetened Iced coffee, add sugar while the coffee...