OJ cheaper as Not from concentrate?

OK so I am in the Chicago land area. I like orange juice... more accurately I LOVE orange juice and I prefer Minute Maid Orange Juice over Tropicana. So I have tried to figure out the cost of concentrate vs not from concentrate and discovered its actually cheaper to buy the 1 gallon of not from concentrate than it is to buy the concentrated oj. How can this be...? Don't question me about the math as to this was my major in college.