You can run a report called "Data Retention Forecase and Compliance" on the storage policies used by this library and you can see exactly why jobs are not being aged and that should tell you what can be done to change it.
Depending on your settings its possible jobs are not being pruned if the copy has not been run and if this is the case then setting them to DO NOT COPY will allow them to be pruned. (again, the report should confirm this)
If all our national holidays were observed on Wednesdays, we could wind up with nine-day weekends
-- George Carlin