If you have a CID you will be retained on thase hours in the exact same way as a permanent teacher. In fact, as a result of a recent decision at the Teachers Conciliation Council, if you have a CID for 18 hours or more, you are entitled to be paid for 22 hours, the max teachers salary. The Circular Letter for this has not been issued yet but the operative date is Sept. 2009. If a particular school has more permanent teachers and CIDs than its quota then it is technically over quota and people who retire or go on career break or job sharing may not be replaced.