Since College Board seems to intend to release a version annually, it makes sense to me that the security needs to be preserved for one year. For example, the exam that we have just received should be protected until after this school year. Then the 2013 version will be released and we will protect that until the end of the 2013-2014 school year, etc.
If this is not the intent of the College Board, please correct me.
Mathematics Department JFK High School 305 Cayuga Creek Road Cheektowaga, NY 14227 (716)897-7800 ext. 1120