Can Statistics Portal Data for Exchange portion of migration project be completely reset?
Some high level facts about the design and behavior of statistics portal.
Statistics data for synchronized mailboxes is kept within SQL project database as set of tables: STATProcessedCollection1-7, STATProcessedItem1-7, STATProcessedMachine, STATProcessedSession1-7, STATProcessedUnit1-7, STATProcessedWorkflow1-7. Statistics Portal in Migration Manager relies on IIS to display information collected in these tables.
Statistics Collection Agent is used to pull information from local mail/calendar agents kept in emwstat.dat file in each agent's folder and place into the project database. There is no functionality of resetting this information and clearing statistic's tables inside the project.
Please also see this Quest Knowledge Base for additional information: