Magento

This may have been answered somewhere else in the forums but I have not been able to find it. I have my site up and running and now I have gotten my second order and it is not calculating the shipping correctly for the total weight of the customers order. We have only gotten a few orders before and they were all the same weight, 1 pound. Now I have an order that totals 12 pounds and it calculated the shipping at the cost for 1 pound.

I have the shipping method as USPS, Flat Rate Box, Regular, Machinable, Priority Mail Flat Rate Box. Am I missing something or how can I fix this. I am shipping the order to the customer at a loss at this point and as far as I can tell everything seems right… HELP!