4 oz. uncooked usually become 3 ounces cooked if the meat is boneless. Shrimp and scallops lose a little more in the cooking so that 3 ounces becomes 2 ounces.
One more question - When it says the weight of the meat on the box, is it talking about cooked or raw?? I know that it probably depends, but in general what have you noticed? I live in Canada and it doesn't state particulars like that.