If for some reason Plesk does not update the statistics properly for a site or you wish to re-run them after changing log files etc it is a simple process.

1. Login to your Plesk server as user “root” using SSH.
2. Run “/usr/local/psa/admin/sbin/statistics --calculate-one --domain-name=<domainname>” – replacing <domainname> with the domain name you need to reprocess the statistics for.