Adler is right. You will be awarded trips in order. If you get a trip, they will go to your next trip request (in order) until the end of your list. If you have 57 hours in makeup and get a 30 hour trip, it will keep filling available trips until you hit 57 + 6 (you can go over by no more than 6 hours).

If you are very senior, you will not need to make that many bids. If you are very junior, you may want to put down every trip that you are willing to take. The system goes to the most senior bidder, fills all of his trip requests that are available, then goes to the next guy, etc.

Good luck