The stored number was off then. The "actual" number list is what the script counted for each board when it loaded. When you cliked "update" it loads the page again but adjusts the stored count to what it actually counted while loading.
Donate to UBBDev today to help aid in Operational, Server and Script Maintenance, and Development costs.
Please also see our parent organization VNC Web Services if you're in the need of a new UBB.threads Install or Upgrade, Site/Server Migrations, or Security and Coding Services.