Please review the GMT/US Time zone specifications for:

Introduction to SQL Server Statistics

September 7th 12:00 PM EDT (GMT -4)

AND

Designing High Performance I/O for SQL Server

September 8th 12:00 PM EDT (GMT -4)

The event on 09/07 appears to be correct, but the event on 09/08 may be incorrect as the LM displays:

Title : Designing High Performance I/O for SQL Server

ID : S29G25

Start Time : Sep 8, 2010 11:45 AM (MDT)