What's the point of defining the teachers' provisions?

When creating or modifying timetables (for example, monitoring a replacement), you can verify that the number of hours allocated to a teacher does not exceed the number of hours provided for in his or her contract, if his or her provision has been previously entered: when you assign a teacher to a course, EDT informs you of the tally. If the provision is exceeded, the number of hours allocated appears in red (without preventing the teacher from being assigned if necessary).