You are correct. An ounce of fluid is barely over an ounce of weight, so 12oz*12 cans = just over 144 oz of weight. 144/16 is a little over 9 lbs. Throw in the small weight of the aluminum and plastic and you got yourself around 10 lbs.
Anyone else at Midnight Madness? What the hell is up with no beer?? It's overall been lamer since they moved it from downtown, but I kinda thought its whole identity was a fun after party with beers.