Are you running your sendnotice.php cron script? If you run that cron script then expired ads do not show on your install period of this I am sure.
As far as the expired que any expired ad will show and you need to manually delete each ad. I can not specifically test the feature right now but it has not changed in a long time. Perpage is carried to the next page as well as cat and I show both typecast in the present version.
You can send me a PM to see your site
We can always look at ways of improving this in the future.