Yes, the system reports on reply times during business hours (and outside of business hours).
Business hours can be set on the account level (across all mailboxes) as well as on individual mailboxes if necessary.
To change business hours on the account level, go to Tools > Settings > Business Hours and Leave Management > Edit Business Hours.
To change business hours for a specific individual mailbox, go to Tools > Mailboxes > Actions > Edit, on the mailbox that you would like to set the business hours for.