Trying to Shrink Database

I’ve got auto archiving setup and I’m running a Cron job to try to shrink my DB down. At the end it says 257 skipped because no new visit since the last script execution. On the privacy settings page it says DB size is 1.6GB and after purge 335.4 but I can’t get it to purge.

Oh and it’s ‘offline’ as in it’s not getting new data right now.

I’m sure I’m missing something as I’m not getting errors but what could i be missing?