Discount trial class from tuition

If a person registers for a FREE trial class and wants to enroll right after the class was taken, the system will not prorate that class and will charge a full tuition. The system should have the possibility to discount that FREE class automatically and only charge the next classes or weeks that the costumer should be paying for. If the class is given once a week and that month she took the 1st class as a trial, then when she enrolls after the class, the system should charge for 3 weeks instead of 4 because the first one was a trial.

We have seen it works better to enroll a student right after the trial is done when their experience during the class is still fresh rather than waiting until next day when the experience is no longer fresh and the rush is gone.