Hi aquarius.
Their website seems wrong, it does not show the costco product... the website shows the 14oz bottles at 160 calories, but..... costco sells 8.5oz bottles with 160 calories, labelled as "light", and 20g of protein. So basically you are getting the same calories and protein out of costco's 8.5oz bottle as you are out of the 14oz one on their website.... not sure, I guess it's a different formula. To me it seems "sneaky" by cytosport, because they will charge more money for the 14oz than they will for the 8.5oz, but both contain the same stuff.... the 14oz just has more water I guess.