Also I found that time is different from current system time.

The ADV_Outlook_Log.txt file date is 25.11.2010 15:54, the first row of this file starts with 3:32:19 PM and the last row – 3:54:47 PM, but all the Sent Items have current date (25.11.2010) and time between 9:57 and 9:59 (24h format).

It looks like time reset is made not during the process of import (only 2 minutes time difference for 1551 items).