I have spent ages and ages trying to find out how to manually update the webstats for Plesk with Linux.
basically the problem i was having is, i would add a new domain within plesk and days after the webstats gave that “Wait at least 24 hours message” and wouldn’t update. I am not sure on a perminat fix but you can manually flush / update the stats on your sites.
Log in to your server via SSH command and simply type..
/usr/local/psa/admin/sbin/statistics
It will go though and flush and re-update . This only works with Plesk and Linux install.