A Lufthansa A320 overran a runway during landing some time ago. The Captain attempted to deploy spoilers manually (due to no auto deploy)....as a result all he got was 'partial' deployment and a subsequent overrun. I believe a software change came in as a result of that accident which modified the normal 'auto spoiler deployment' criteria, but the manual slection still gives only partial extension.
This is one area where I prefer Boeing.