Hi tweetypie, I was under the impression that each institution has a FINITE amount of Stafford funds to disburse. In other words, if a university has x amount of Stafford money, it is up to the FAO to divide the available funds among its students...sometimes x amount doesn't go far enough to meet everyone's needs (like me ).
Schools can choose to cap the amount you can borrow through stafford loans anywhere between 18500 and 38500. You may have hit your school's cap. I would encourage you to call and ask, however. Frequently things in your award that don't look right actually aren't, and if it was a mistake, it can be fixed. One of my three offer letters had an EFC 8K higher than the other two. I called and asked, and lo and behold, the person entering my info into the computer had overlooked some crucial details. It got fixed, but only 'cause I called.