Backup Exec Tapes and Media Sets

I have a client who is running multiple jobs within backup exec 2012 and I have having issues getting the tapes to automatically overwrite.  They keep getting full and a format is required prior to the backup running.  What i would like is a 5 day media set and for all jobs to backup data without the tapes overwriting.

I have setup my daily media set and also ensured the first job overwrites and the other jobs append to media.

Why is the tape getting full every night.  It seems when the first job runs the overwrite protection kicks in on the tape and the other jobs do not run.