Clients have reported that when Daylight savings begins around 2nd October BBIS email delivery was delayed by an hour from what was expected.  The particular users were users in a different office where Daylight savings time had not yet begun.  The time zone in BBIS is set in Administration>Sites & Settings and is relative to GMT.  Users in other time zones may need to send emails later/earlier to account for daylight savings time as BBIS uses the time zone in Administration>Sites & Settings.