As long as you do not work more than 475 hours and you are younger than 26, you retain the right to the growth package. If you work more than 475 hours, you retain your growth package. If you work more than 475 hours, you retain your growth package for the months in which you work less than 80 hours.
If you work more than 80 hours per month as a non-job student, then you lose your child benefit for that month. Because of your higher income, also take into account your taxes and whether you remain a dependant.