InfoPath Dev

I have a consultant time sheet I am working on. It is housed in a sharepoint site with the "My Forms" view so they can only see thier own. After each daily entry, the total hours are calculated. That part works fine.

The problem is, there will be a new time sheet submitted every two weeks. Therefore, a totally differnt xml file will be created. I need to have a box that displays the total hours the consultant is contracted for, updated each time. For example, Joe Shmo is contracted for 400 hours. He worked 80 hours the first two weeks. He is now ready to start a fresh time sheet. That sheet needs to autmatically display 320 to reflect previous time sheets submitted.

How can I do this?

Thank you.

The easiest way I could think of to solve this problem is as follows:

1) Promote the total hours worked per timesheet into the form library.
2) In the timesheet form, establish a connection to this form library.
3) Perform calculations to add all of the previous hours together (from the promoted properties), and then in the form display how many hours are remaining.

The main problem here would be storing the total hours available (400 in this case) - I guess you could use a SharePoint list or some other configuration method.